Option to clear other cached data like MDL

[lilggamegenius]

like #603 but for other parts

[CapsAdmin]

This is actually not possible because once a gma archive has been mounted you can't delete it. You can work around it by salting the hash that pac3 generates for it though.

[lilggamegenius]

Maybe you could add some option that means that you're currently editing the model so it stores it in a special temp folder that increments a counter. This way you can always load a new version of the model.
Similar to pac3_cache/testing/somehash-test1/<name>.mdl then you could clear the testing folder when pac starts or something.