Scroll-Wheel Weapon Switch

Just edited a bunch of lines in inputs_keyboard.scr file.

A bit of warning: It uses both 3 and the wheel movements to go to both previous and next weapons.  So if you switch the keys (specifically 3 and wheel down), you'll need to reset to defaults to get it working again.  If anyone knows a fix, i'll adjust that.

Also seems to have a slight merging issue if not done manually at the moment, info on the sticky post.  Otherwise did a pre-merge of the mod and holster in the optional files.

And to just note, slot 1 needs to have something in it for the upwards scroll to work, this applies to the default equipment switch anyways.  Just pointing it out to avoid possible confusion.