* Make isRestore work in the cluster.
This covers sharded collections with default sharding and non-default
sharding.
* always use locally generate revision ids for storing and looking up documents
* simplify index API a bit
* fix fulltext index removal performance, simplified code
* updated CHANGELOG
* fix hanging test
* try to fix shutdown problem
* improve fulltext query performance
* fixed duplicate var
* removed obsolete code
* fix some shutdown races
* do not call ensureIndex that often