New RPC commands: getblockhash and getblock #727

This is designed to work nicely with 'gettransaction' and new 'blockhash'/'blockindex' information returned in listtransactions; it is modified from the 'getblock' that was in my monitorreceived patch.

getblockhash <index> Returns hash of block in best-block-chain at <index>.

e.g. getblockhash 0 returns 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f (genesis block hash)

getblock <hash> Returns details of a block with given block-hash.

e.g. ./bitcoind getblock $(./bitcoind getblockhash 0) returns the genesis block:

{ "hash" : "000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f", "blockcount" : 0, "version" : 1, "merkleroot" : "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b", "time" : 1231006505, "nonce" : 2083236893, "difficulty" : 1.00000000, "tx" : [ "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b" ], "hashnext" : "00000000839a8e6886ab5951d76f411475428afc90947ee320161bbf18eb6048" }

ACK

though I still prefer original getblock/dumpblock, which provides more information than 'gettransaction' presently provides: full script dump, full expansion of vin/vout, etc. Much more raw and programmer-oriented.

If you feel like a little after-Christmas coding, I'd be OK with an expanded gettransaction that returns all the gory details. Or that returns information for non-wallet transactions.

ACK

I would lean towards adding a separate 'dumptx' that returns all the gory details, keeping it separate from current gettx.

But that's separate from this pull request...