Change bitcoind config object from clientConfig.rpc to clientConfig.bitcoind

Now always call getAccount, not new client.Account
Factor testing class out to test-payment-lib.js
Specify that this includes bitcoind as well as Bitcoin-Qt
Fix demo to use new API
Various small documentation improvements
Merge branch 'master' into rpc

Conflicts:
	doc/code/bitcoin-nanopayment.html
	doc/code/jsbn-patched.html
	doc/code/test-payment.html
Merge branch 'rpc'