Adds a "walletconflicts" array to transaction info; if
a wallet transaction is mutated, the alternate transaction id
or ids are reported there (usually the array will be empty).
Metadata from the original transaction is copied to the mutant,
so the transaction time and "from" account of the mutant are
reported correctly.
Extend CMerkleTx::GetDepthInMainChain with the concept of
a "conflicted" transaction-- a transaction generated by the wallet
that is not in the main chain or in the mempool, and, therefore,
will likely never be confirmed.
GetDepthInMainChain() now returns -1 for conflicted transactions
(0 for unconfirmed-but-in-the-mempool, and >1 for confirmed).
This makes getbalance, getbalance '*', and listunspent all agree when there are
mutated transactions in the wallet.
Before:
listunspent: one 49BTC output
getbalance: 96 BTC (change counted twice)
getbalance '*': 46 BTC (spends counted twice)
After: all agree, 49 BTC available to spend.
