It should avoid a lot of the issues sending more than half the
wallet's contents due to change.
Actual output selection is still random. Changing this would
improve the matching of transaction amounts to output sizes,
but may have non obvious effects on blockchain analysis.
Mapped to the new transfer_new command in simplewallet, and
transfer uses the existing algorithm.
To use in RPC, add "new_algorithm: true" in the transfer_split
JSON command. It is not used in the transfer command.
wallet RPC now uses wallet2::create_transactions and wallet2::commit_tx instead
of wallet2::transfer. This made it possible to add the RPC call /transfer_split, which
will split transactions automatically if they are too large. The old call to
/transfer will return an error stating to use /transfer_split if multiple
transactions are needed to fulfill the request.
