_info should return doc_count/seqno from stores

fixes problem where the db is being updated and doc_count is incremented
but _info is returing an old value. since doc_count is cached on writes then
_info should use this cached value instead.
Merge branch 'master' of https://github.com/tahmmee/pouchdb

Conflicts:
	src/adapters/pouch.leveldb.js