SERVER-6071 prevent spinning on primaries
SERVER-9518 Make sure internal user stays in the user cache
SERVER-6071 add sleep on connection failure to avoid spinning
SERVER-10452 mongos should select cursor based on cursorid, not sharding state
Make doingMerge a property of DocumentSourceGroup rather than ExpressionContext

Prep for sharded $out (SERVER-10097). Will need to be able to send a
merging $group to a shard.
SERVER-10097 sharded $out

Note that all sharded aggregation tests now go through the
"merge-on-mongod" codepath now rather than the "merge-in-mongos"
codepath.
Support cursors returned from sharded aggregation

Follow-up to SERVER-5932
Make DocumentSource handling more generic
Error out if $out collection is sharded
Add a multi-version (2.4 and 2.6)  test for sharded aggregation.
Include missing header
Fix C++11 builder
SERVER-10097 Visual Studio -- add db/pipeline/document_source_merge_cursors.cpp
print more info on small-oplog test failures
SERVER-10163: don't check okForStorage during replication
SERVER-6399: validate with okForStorageAsRoot on inserts
SERVER-6399: Support replacement with empty doc and log that
SERVER-6399: revert counting to number matched, including noops
SERVER-6399: fix unit tests after 'Support replacement with empty doc and log that' commit