This modifies commits provided by @petertodd to use the terms "pubkey
script" and "signature script" instead of other terms.
* Rename "scriptPubKey" and "output script" to "pubkey script"
(suggested by @luke-jr). We leave a token "scriptPubKey" at the point
where we define pubkey script so that searchers can find it.
* Rename "scriptSig" to "signature script" (suggested by @luke-jr). We
also leave a token "scriptSig" at this definition point.
* Rename "redeemScript" to "redeem script"
* Defined ECDSA on secp256k1 curve as the crypto used in the Transaction
section and added references to secp256k1 private/public keys and
signatures.
* Removed "The Parts Of A Transaction" illustration by commenting it out
in the HTML. Shoehorning the pubkey/signature script terms into this
image was becoming difficult, and I'm not very fond of that
illustration anyway. I'll see if I can think of a nicer replacement
illustration for some point in the future.
* Add a short paraphrased version @petertodd's description of scripts as
generalized crypto.
* Updated all the illustrations which referred to either pubkey scripts
or signature scripts to use these terms.
Thanks also (in alphabetical order) to @cbeams, @mikehearn, and
@tgeller, among others.
The last pre-squash commit was: c2b8d562aa107c7b68c60946cea14cdccc5159ad
