Actually delete the asio io_service when we are done with it since that
will delete any left over tasks in the queue.
This makes deletion order more predictable.
The new UnspentOutputDatabase classes are only very loosly a database, we
purely register and store unspent outputs there. But unline a DB we don't
allow modification (just insert and delete).
This replaces the coin-db (which was based on leveldb) and as first goal
this gives us a higher level of stability. The level-database was known
to give corruption issues.
Notice that users will need to do a manual reindex on first update.
So the service only noticed new stuff happening, like a transaction
coming in or block being mined.
With this change we get a little smarter and look in the current mempool
as well to try and match a transaction.
This should be very useful for clients that lose network connection
briefly.
This service allows one to connect it and register any number of
bitcoin-addresses which will then cause any transaction or block
coming in the future lead the subscriber to get notified about
such events.
The change signifies that the server is not just for admin purposes it
will become the preferred way for all subnet-local interactions.
Notice that we still have the JSON based RPC protocol as fallback.
TomZ