SERVER-16016 WiredTigerRecordStore::Iterator should not try to restore its state if it is EOF
SERVER-15645: clean up WiredTigerRecordStore::insertXXX
SERVER-15645: allow writes to oplog in IX by managing reads to block on oldest ts
SERVER-16046: only one thread should cleanup capped collections
Fix cache_size tuning error from commit:
1b446f240856cf93b32fcc62e1980d9cc2f42f87
Merge remote-tracking branch 'upstream/master'