Bug 2429 allow selection of associated namespace in recent changes

Bug 2429 allow selection of associated namespace in recent changes

Done by adding yet another checkbox in Special:RecentChanges. The feature
also support namespace inversion.  For example, if you have selected
the TALK namespace with inversion and associated namespace, you will
be shown any changes which is not NS_MAIN or NS_TALK.

Tests:

SpecialRecentchanges tests only this feature. I had to filter out
the rc_timestamp condition which might cause trouble if the test
suite is run on another day. A better solution remains to be implemented.