Errors (with patch)

As reported by @dreamermates, in this unresolved thread, errors are thrown from the filterVersions method in lib/Garbagecollector.class.php. This line:

preg_match_all('#^(?P<group>.+)-(?P<token>[^\-\.]+).css$#sU', $file, $m, PREG_SET_ORDER);

is using the wrong function. It should be this (note the pattern is also fixed):

preg_match('#^(?P<group>.+)-(?P<token>[^-.]+)\.css$#sU', $file, $m);

This causes lots of Undefined array key “group” warnings but mainly fails to do its task.