Loading the same wallet as the currently loaded one would autosave
the current state after loading it, leading to some kind of rollback
effect. We now save before loading to avoid this. If loading fails,
it means the current wallet will be saved (or maybe not, depending
on where the failure occurs: most of the sanity checks occur before
saving). There is a new autosave_current flag to open/restore calls
so the (enabled by default) autosave can be skipped.
Also throw exceptions instead of print+exit, since that makes
the error print last, below the python stack trace, where it's
much less easy to miss it.
It allows one to connect to a running daemon or wallet, and use
its RPC API from python.
Usage: python -i console.py <port>
It will detect whether it's talking to a daemon or wallet and
initialize itself accordingly.
