Item pickup working

You can pickup items and use them, but the code is kind of sloppy and
it's not working 100%. Still trying to get it to only work in certain
areas (doors) but I can't quite get it. Easy enough to make a sprite
appear for an inventory HUD, but we might want to just have a counter go
up on the HUD instead so we can get multiple keys. Will keep working
tomorrow.
Also, sorry if I submitted this wrong or something! My first time
submitting code haha. Let me know if I've done something wrong.