[Fix] Ensure tvshowmatching regexes are run caseless

Following #2851, it turns out the tvshowmatching regexes are in fact not run caseless.  
See http://forum.xbmc.org/showthread.php?tid=168175 for more details.

The second commit just simplifies the default tvshowmatching regexes by removing the unnecessary case distinctions.  Not wholly necessary, but the redundancy has always bugged me.