Support for executing and confirmation an outgoing send from the wallet in a single transaction.

[Vovanchik25071982]

Support for executing and confirmation an outgoing send from the wallet in a single transaction.
msg.sender is used for one of the signatures and data with ecrecover is used for another "signature".

How to generate the signature with eth.sign:
uint expireTime = 1863771845; // 10 years in the future
uint sequenceId = 1; // or the next sequence Id obtained using getNextSequenceId();
bytes32 sha3 = sha3(to, value, data, expireTime, sequenceId); // see tests for examples how to build this
bytes signature = eth.sign(owner1, sha3); // sign the sha3 using owner1

Example usage in tests:
https://github.com/BitGo/eth-multisig-v2/blob/master/test/wallet.js#L1075

Originally posted by @bencxr in ethereum/dapp-bin#68