SERVER-16262: Add test case for Map/Reduce WriteConflict
Create CurOp on stack rather than heap for write commands
special case _id index key generation
SERVER-16519: restart session before backing off after write conflict
SERVER-16519: remove commented out code
SERVER-16519: turn on printing write conflict traces via setParameter
SERVER-16519 SERVER-16235: WT capped conflict fix and stop special casing oplog
SERVER-16519: fix linking of WriteConflictException
Merge remote-tracking branch 'upstream/master'