SERVER-12650 make syncSourceFeedback's oplogreader effectively single threaded
Bulk find() requires selector, SERVER-12553.

Squashed:
- Update comments in bulk_api.js.
- Throw Error from invalid Bulk operations, not strings

Signed-off-by: Matt Kangas <matt.kangas@mongodb.com>
SERVER-12654 append additional information to inconsistent config writes

Signed-off-by: Matt Kangas <matt.kangas@mongodb.com>
SERVER-12515 Unable to move hashed shard key chunks created by numInitialChunks
SERVER-12625: skip oplog entries for no-op fields
SERVER-12382 Windows hosts do not honor --maxConns values > 20,000
SERVER-12304 Query concurrency -- 2.6 regression
Merge remote-tracking branch 'upstream/master'