Metatag tweaks + Fix for issue 359 & 362.

* Numeric Score vote blocks are now managed by theme.php (so themes can hide/move them).
* Metatags now support using : as a seperator (= still works). Also updated the metatag docs.
* Added a width & height metatag. Handy if you want to find something specific (I.E tall/wide images).
* Fixed search not working properly when aliasing to multiple tags. Fix for issue #359.
* Use headers for filename/extension when uploading via transload. Fix for issue #362.
* Added an order metatag which allows ordering search results by id/width/height/filesize ASC/DESC.

Not too sure about using a global var for setting/getting the SQL for the order metatag.
It works..but feels like I'm missing a better way of doing this.