SERVER-15280 Validate copydb command "todb" field
SERVER-13635: fix test for kv that restarts engine
SERVER-14352: move rocks engine to kv interface
SERVER-13635: do not use collection names for file names in kv engine to avoid confusion
SERVER-13635: use new index command when checking shard keys
SERVER-13635: update many sharding tests to work with other storage engines
SERVER-13635: make bench test more reliable
SERVER-14352: turn off some lint options for rocks
SERVER-13635: make some tests more generic for some engines
SERVER-14425 Cleanup LockerImpl

* Remove unused methods
* Make references to the lock manager to go directly through the instance
* Add comments
SERVER-14425 Performance optimization in LockManager for the unlock path
SERVER-14425 Make MMAP V1 code in LockerImpl conditionally compiled

This change cuts down on the locking work that other storage engines have
to do.
SERVER-13635: do not invalidate doc when using doc locking
SERVER-13635: make sharding test more robust
SERVER-14425 Add MMAP V1 check to invariant
SERVER-13635: fix typo in _recordStore
SERVER-13635: abstract storagesize per db for listDatabases
SERVER-13635: make capped dbtests more generic
SERVER-13635: move mmapv1 specific test to right place
SERVER-13635: make noPassthroughWithoutMongod tests storage engine agnostic