SERVER-15541 RecoveryUnit::commitAndRestart to avoid WriteUnitOfWork
SERVER-15541 SERVER-15652 implement timing-based yielding
SERVER-15713: do not buffer replicated ops once primary
SERVER-15060: remove failing large set test
SERVER-15733 Wait longer for a primary in jstests/replsets/replsetprio1.js.

With the 30 second lease time, it is possible for it to take just over 30 seconds to elect
a new primary in replsetprio1.js.  Bump the wait time in the test to 60 seconds.
Merge remote-tracking branch 'upstream/master'