[Content] Add devnet details (#40)

* content - Add devnet details
 - Description in examples section
 - Glossary entry and updated testnet/regtest

* content - Devnet P2P
 - Add to start string and spork key tables

Closes #36

_data/glossary/en/devnet.yaml

@@ -0,0 +1,32 @@
+---
+# This file is licensed under the MIT License (MIT) available on
+# http://opensource.org/licenses/MIT.
+
+required:
+                                           #-------------40 characters-------------#
+    title_max_40_characters_no_formatting: Devnet, Development Network
+
+    summary_max_255_characters_no_formatting: >
+        A development environment in which developers can obtain and
+        spend duffs that have no real-world value on a network that
+        is very similar to the Dash mainnet. Multiple independent devnets can
+        coexist without interference. Devnets can be either public or private.
+
+    synonyms_shown_in_glossary_capitalize_first_letter:
+        - Devnet
+
+optional:
+    synonyms_and_pluralizations_not_shown_in_glossary:
+        - devnets
+        - devnets mode
+        - devnets modes
+        - development network
+
+    not_to_be_confused_with_capitalize_first_letter:
+        - Regtest (a local testing environment where developers can control block generation)
+        - Testnet (a global testing environment which mostly mimics mainnet)
+
+    links_html_or_markdown_style_capitalize_first_letter:
+        - "[Devnet mode](/en/developer-examples#devnet-mode) --- Developer Examples"
+
+---

_data/glossary/en/regression-test-mode.yaml

@@ -23,6 +23,7 @@ optional:
         - regtest modes
 
     not_to_be_confused_with_capitalize_first_letter:
+        - Devnet (a public or private development network which mimics mainnet)
         - Testnet (a global testing environment which mostly mimics mainnet)
 
     links_html_or_markdown_style_capitalize_first_letter:

_data/glossary/en/testnet.yaml

@@ -22,6 +22,7 @@ optional:
         - testing network
 
     not_to_be_confused_with_capitalize_first_letter:
+        - Devnet (a public or private development network which mimics mainnet)
         - Regtest (a local testing environment where developers can control block generation)
 
     links_html_or_markdown_style_capitalize_first_letter:

_includes/devdoc/example_intro.md

@@ -26,6 +26,13 @@ Once installed, you'll have access to three programs: `dashd`,
 * `dash-cli` allows you to send RPC commands to `dashd` from the
   command line.  For example, `dash-cli help`
 
+{% endautocrossref %}
+
+### Configuration file
+<!-- no subhead-links here -->
+
+{% autocrossref %}
+
 All three programs get settings from `dash.conf` in the `DashCore`
 application directory:
 
@@ -53,8 +60,8 @@ directory:
 chmod 0600 dash.conf
 ~~~
 
-For development, it's safer and cheaper to use Dash's test network (testnet)
-or regression test mode (regtest) described below.
+For development, it's safer and cheaper to use Dash's test network (testnet),
+regression test mode (regtest), or a develper network (devnet) described below.
 
 Questions about Dash use are best sent to the [Dash forum][forum
 tech support] and [Discord channels][Discord channels]. Errors or suggestions related to

_includes/devdoc/example_testing.md

@@ -109,3 +109,63 @@ configuration directory locations on various operating systems. Always back up
 mainnet wallets before performing dangerous operations such as deleting.)
 
 {% endautocrossref %}
+
+### Devnet Mode
+{% include helpers/subhead-links.md %}
+
+{% autocrossref %}
+
+Developer networks (devnets) have some aspects of testnet and some aspects of
+regtest. Unlike testnet, multiple independent devnets can be created and coexist
+without interference. Each one is identified by a name which is hardened into a
+"devnet genesis" block, which is automatically positioned at height 1. Validation
+rules will ensure that a node from `devnet<!--noref-->=test1` never be able to
+accept blocks from `devnet<!--noref-->=test2`. This is done by checking the
+expected devnet genesis block.
+
+The genesis block of the devnet is the same as the one from regtest. This
+starts the devnet with a very low difficulty, allowing quick generation of a
+sufficient balance to create a masternode.
+
+The devnet name is put into the sub-version of the `version` message.
+If a node connects to the wrong network, it will immediately be disconnected.
+
+To use devnet, use the argument `-devnet=<name>`<!--noref--> with `dash-cli`,
+`dashd`or `dash-qt` or add `devnet<!--noref-->=<name>` to your `dash.conf` file as
+[described earlier](#configuration-file).
+
+Devnets must be assigned both `-port` and `-rpcport` unless they are not
+listening (`-listen=0`). It is possible to run a devnet on a private (RFC1918)
+network by using the `-allowprivatenet=1` argument.
+
+{% endautocrossref %}
+
+Example devnet start command:
+
+{% highlight bash %}
+> dashd -devnet=mydevnet -rpcport=18998 -port=18999 -daemon
+Dash Core server starting
+{% endhighlight %}
+
+{% autocrossref %}
+
+You can now use Dash Core RPCs prefixed with `dash-cli -devnet=<name>`<!--noref-->.
+
+Devnet wallets and block chain state (chainstate) are saved in the `devnet-<name>`<!--noref-->
+subdirectory of the Dash Core configuration directory. You can safely
+delete the `devnet-<name>`<!--noref--> subdirectory and restart Dash Core to
+start a new devnet. (See the [Developer Examples Introduction][devexamples] for default
+configuration directory locations on various operating systems. Always back up
+mainnet wallets before performing dangerous operations such as deleting.)
+
+Eventually, there may be many public and/or private devnets that vary in size
+and function. Providing the correct devnet name and the seed node of the network
+will be all that is required to join.
+
+An old devnet can be easily dropped and a new one started just by destroying all
+nodes and recreating them with a new devnet name. This works best in combination
+with an automated deployment using something like Ansible and Terraform. The
+[Dash Cluster Ansible](https://github.com/dashpay/dash-cluster-ansible) provides
+a way to do this (currently a work-in-progress at an early development stage).
+
+{% endautocrossref %}

_includes/devdoc/ref_p2p_networking.md

@@ -7,6 +7,8 @@ http://opensource.org/licenses/MIT.
 ## P2P Network
 {% include helpers/subhead-links.md %}
 
+<!-- __ -->
+
 {% autocrossref %}
 
 This section describes the Dash P2P network protocol (but it is [not a
@@ -37,6 +39,7 @@ The following constants and defaults are taken from Dash Core's
 | Mainnet | 9999         | 0xBD6B0CBF  | 0xBF0C6BBD                      | 0x1e0ffff0
 | Testnet | 19999        | 0xFFCAE2CE  | 0xCEE2CAFF                      | 0x1e0ffff0
 | Regtest | 19994        | 0xDCB7C1FC  | 0xFCC1B7DC                      | 0x207fffff
+| Devnet  | User-defined | 0xFFCAE2CE  | 0xCEE2CAFF                      | 0x207fffff
 
 Note: the testnet start string and nBits above are for testnet3.
 
@@ -1339,6 +1342,7 @@ Core can be found in `CPubKey::RecoverCompact`). The hash is a double SHA-256 ha
 | Mainnet | 04549ac134f694c0243f503e8c8a9a986f5de6610049c40b07816809b0d1<br>d06a21b07be27b9bb555931773f62ba6cf35a25fd52f694d4e1106ccd237<br>a7bb899fdd |
 | Testnet3 | 046f78dcf911fbd61910136f7f0f8d90578f68d0b3ac973b5040fb7afb50<br>1b5939f39b108b0569dca71488f5bbf498d92e4d1194f6f941307ffd95f7<br>5e76869f0e |
 | RegTest | Undefined |
+| Devnets | 046f78dcf911fbd61910136f7f0f8d90578f68d0b3ac973b5040fb7afb50<br>1b5939f39b108b0569dca71488f5bbf498d92e4d1194f6f941307ffd95f7<br>5e76869f0e |
 
 The following annotated hexdump shows a `spork` message.