SERVER-7937 Additional ReplicaSetMonitor Tests

Signed-off-by: Matt Kangas <matt.kangas@mongodb.com>
SERVER-12682 Add warning on OS X if libc++ is selected and osx-version-min is < 10.7.

Signed-off-by: Andrew Morrow <acm@10gen.com>
Merge remote-tracking branch 'upstream/master'