SERVER-12774 added nscanned and nscannedObjects to slow query log
SERVER-12873 add more plan ranking dbtests
SERVER-12896 MongoRunner fixes to make multiversion tests run on Windows

The system programs either come versioned in the form of
<utility>-<major.minor> (e.g., mongorestore-2.4) or just <utility>. If
change_extension is called on this string, it will replace the minor
version component and the binary will not be found.

In pre-2.6.0rc0 versions, we did not have the server shutdown event and
the stop commands needs to use the old method of connecting on the admin
port and invoking shutdown.
Merge remote-tracking branch 'upstream/master'