pouchdb/pouchdb — pull request #2933 by nolanlawson (2014-10-31 16:41:17+00:00)
Title: (#2931) - parallel compaction keeps db integrity

Contains two fixes:

1. adapter.js no longer passes the rev_tree to the underlying
adapter. The adapter is expected to recalculate, since other-
wise the database may change in the interim.
2. leveldb.js has a global write lock for all readwrite operations,
similar to how WebSQL/IndexedDB work under the hood. I'm not
100% satisfied with that, but it's better for the db to be
correct than to be fast.