Commit 2eeb6b randomized the order of input and output notes,
but this is now known to prevent the chaining of multiple joinsplits
in a single transaction. The root cause has yet to be determined.
This patch is a temporary fix and disables the shuffling of input
and output notes. It also adds a chained joinsplit test to the
python qa test suite.
Extra parameter added to AvailableCoins to include or exclude Coinbase coins.
SelectCoins, used for sending taddr->taddr, will exclude Coinbase coins.
Added qa rpc test and a runtime parameter -regtestprotectcoinbase to enforce
the coinbase->zaddr consensus rule in regtest mode.
