wait for bitcoind on startup
Merge pull request #1 from m0mchil/fix_missing_bitcoind

wait for bitcoind on startup
Bugfix: Serialized numbers are signed, so need an extra \x00 in the case of 0x80...-0xff...

Function body taken from Eloipool's bitcoin/script.py encodeUNum function (does not work for zero or negative numbers)
Merge pull request #2 from luke-jr/bugfix_sernum

Bugfix: Serialized numbers are signed, so need an extra \x00 in the case of 0x80...-0xff... This was a reason for rejecting v2 blocks on testnet.
Merge in from parent... Luke sign fix
Added support for backup bitcoind backends (yes, I have had bitcoind crash a couple times)