Revamp undo / pending process

Added new database of enumerated properties that can be set/updated
using the transactional db model.  This should potentially solve the
undo/redo bugs that were sure to show up under the old model.
Merge branch 'master' of https://github.com/BitShares/bitshares_toolkit into BitShares-master
Merge branch 'BitShares-master' into wallet_test