Add a method Cursor() to CCoinsView that returns a cursor which can be
used to iterate over the whole UTXO set.
- rpc: Change gettxoutsetinfo to use new Cursor method
- txdb: Remove GetStats method - Now that GetStats is implemented in
terms of Cursor, remove it.
Previously it would break if you flushed a parent cache while there was a child cache referring to it. This change will allow the flushing of parent caches.
Make sure that chainparams and logging is properly initialized. Doing
this for every test may be overkill, but this initialization is so
simple that that does not matter.
This should fix the travis issues.
