General platform-inspecific fixes, FireHoldTakeover, ClearBoundKeyR

Ok,

I figured out I need to create a branch for every pull request (unless I want to make a pull request for the whole fork / plan not to work on it anymore). So this 

Here's just the platform-inspecific things. Actually, I've forgotten I've also added the ability to clear a bind. On a PC, it's not really needed - but still nice! On a device, where there is only limited amount of buttons, it is imperative, since there is no "junk" button to set a non-wanted feature to.