This changes the behavior of the rescan RPC to automatically set the
client up for transaction notifications for transactions paying to any
rescanned address and spending outputs in the final rescan UTXO set
after a rescanned is performed through the best block in the chain.
`searchrawtransactions` can return multiple transactions. Previously the documentation erroneously had return examples showing only a single tx for each case.
* The documentation previously presented the output for the `non-verbose` case as a single json string, instead of an array of json strings.
* Similarly, for the `verbose` mode, the documentation detailed the output as a single json object, instead of an array of json objects.
* Address index is built up concurrently with the `--addrindex` flag.
* Entire index can be deleted with `--dropaddrindex`.
* New RPC call: `searchrawtransaction`
* Returns all transacitons related to a particular address
* Includes mempool transactions
* Requires `--addrindex` to be activated and fully caught up.
* New `blockLogger` struct has been added to factor our common logging
code
* Wiki and docs updated with new features.
