There will need to be some more refactoring for these changes to be
considered complete/correct, but for now it's working.
new daemon cli argument "--db-type", works for LMDB and BerkeleyDB.
A good deal of refactoring is also present in this commit, namely
Blockchain no longer instantiates BlockchainDB, but rather is passed a
pointer to an already-instantiated BlockchainDB on init().
Everything except actually *using* BlockchainBDB is wired up, but the db
itself is not yet working. Some error about user mem not large enough.
I think I know what this error means, but I can't determine the cause.
Notes: BerkeleyDB does not allow 0-indexing in its recno type databases,
so block numbers *in the database* will be 1-indexed. Modifications
to indexing have been made as needed.
LMDB implementation code copy/paste/modified into the Berkeley DB
implementation. Need to test if it builds, then if it works, and so on,
but the code is all there.
