SERVER-13489 move possible disk access out of index cursor ctor
SERVER-13522 Cleanup a couple of encapsulation violations and add coments.

There are no functional changes, just a cleanup.
SERVER-13516 When failing to bulk right copy don't access rep after resolving
SERVER-13523 Use a tiny number of fast reps in debug builds
SERVER-13500 prevent syncSourceFeedback segfault by not allowing NULL members to be added to _members map
Merge remote-tracking branch 'upstream/master'