SERVER-15562 Search neighbors for density estimation with 2d index
SERVER-10515 removed unused file mongos_persistence_stubs.cpp
SERVER-15887 Add tests for ipv6 hostname parsing.

Closes #846

Signed-off-by: Benety Goh <benety@mongodb.com>
SERVER-14638: Move global sethbmsg into ReplCoord
SERVER-15869: Provide config version for each member in replSetGetStatus
SERVER-15867: primary should response to heartbeats as electable
SERVER-15880 AutoGetCollectionForRead should always free its collection lock
SERVER-15880 Delete path should not try to create database
SERVER-15824 renameCollection should commit the destination coll drop
SERVER-13951 Fix rollback of CollectionMap
SERVER-13951 Allow rollback of dropping an index
SERVER-13951 KVEngines shouldn't drop anything when renaming.
SERVER-15496 Code movement to facilitate ripping out legacy replication code
SERVER-15877 Give secondaries 1 second to catch up in replSetStepDown
SERVER-15614 Move inProcCmd to a separate file and clean includes

It is currently in instance.cpp, which is very cluttered. This change is
in preparation for the db.currentOp fix.
SERVER-15044 Remove negation of string from fassert call
BF-615: Reduce memory usage on 32-bit systems even more
SERVER-15580 KeepMutationsStage shouldn't deref invalidated iterator
CollectionInfoCache::reset should reset index keys under X lock
Revert "SERVER-15831 top chunk auto split tests"

This reverts commit ce6a6a4f55c29286860ac1993d5929da0205ff8c.