Basic Hand Click

Modified the mapping of hand coordinates to screen coordinates. This is
less guess and check now, and actually based on unit conversion.
Made a method for getting skeleton info. This way, different classes
(menus) can call the Game1 class when they need skeleton info, making
sure it isn't being run multiple times each game loop.
Very basic hand clicking that requires the user to move his/her hand
forward to click on a button. This is very finnicky, and doesn't always
work.