Remove unused ui-datepicker-month-year class name

git-svn-id: http://textpattern.googlecode.com/svn/development/4.x@5492 2fea6a4d-a838-0410-917b-93a53c48e9d2
Amends to jQuery UI tabs CSS from upstream

git-svn-id: http://textpattern.googlecode.com/svn/development/4.x@5493 2fea6a4d-a838-0410-917b-93a53c48e9d2
Merge remote-tracking branch 'upstream/master'