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.