Version checking, 720p fix, enums.

- Added version checking that runs a check against a build number on
GitHub, if out of date admins will be notified. This can be turned off
using PS.Config.CheckVersion = false.
- Fixed a small issue where the menu wasn't scaling properly on a 720p
screen, resolved this by using the ScrW and ScrH and clamping the values
at 1024, 768.
- Used the unused enums for giving/taking items menus.