* Migrate main node store to LMDB
In preparation to using LMDB as a wallet database, migrate the
node db. There's no point in having 2 key-value stores.
In addition LMDB provides a few advantages as a node db, namely a
much faster build (compared to RocksDb), lesser dependencies and
transactions.
* Migrated p2p store to lmdb, stuff compiles
* More fixes, chain tests starting to pass
* Fixed txhashset rollback messing with block save and general batch delimitation. Chain tests passing.
* rustfmt
* LMDB max map size of 10MB isn't really workable. Half TB seems reasonable.
* Fix wallet tests
* Rather crucial commit was missing
* rustfmt
* Fixing new merged tests following lmdb changes
* rustfmt
* * Make txhashset validation read-only on fast sync to avoid having
a really long open transaction.
* Fix deadlock in new block processing, batch should always be
created within a txhashset lock (when they interact).
* Comment about batch and txhashset interlacing
* Fix store tests to use batch
* Externalize wallet config and seed
* Converted direct read access to file outputs map to an iterator
* Cleaned up and simplified wallet Backend trait:
* No more direct mutable access to internal structures (HashMap)
* Batch interface for all writes
* Remove unneeded read wrapper (read_wallet)
* rustfmt
* First (incomplete) pass at wallet LMDB backend
* Progressing on lmdb backent iml
* Added batch impl for LMDB wallet backend. Pretty much done with it, but not sure how to deal with commit (owned).
* rustfmt
* Wrapping LMDB batch around a refcell to work around borrow rules
* Compilation up to grin chain
* First pass at restructuring the keychain crate and introducing a Keychain trait
* Parameterized everything that had to. Stuff compiles.
* More stuff compiles, fix most tests
* Big merge, pushing down opening the keychain forced adding factory methods on trait
* Test fixes for pool and servers crate
