db: testing: TestDb_CustomComparer: clean up
desc: introduce MemDesc; an in-memory db descriptor
cache: Zap now also delete namespace from namespace table
db: table: use Zap() instead of Purge() in cache when table removed
table: reader: respect RFDontFillCache read flag
db: set RFDontFillCache read flag when creating compaction iterator
Merge branch 'master' of gitlab.svc:glide/goleveldb