* Adds the #bitcoin-dev IRC channel, Bitcoin StackExchange, and
BitcoinTalk Dev & Tech board to the development page.
* Links to that section of the page from the devel docs.
Move existing "regtest / testnet" texts to the new subsection and link to it
Move Bitcoin Core setup instructions in devel-examples
Add a consistent introduction for devel-(guide/ref/examples)
Fix autocrossref.rb to not add links inside {% highlight %} code blocks
Thanks also (in alphabetical order) to @cbeams, @mikehearn, and
@tgeller, among others.
The last pre-squash commit was: c2b8d562aa107c7b68c60946cea14cdccc5159ad