Fixes some bugs in edit game panel:
Undo button would be disabled if the form wasn't valid. Now it's enabled so you can undo the changes you made that made the form invalid.
When you first open the edit game panel, requirements from requirements manager wouldn't show up. They show up unchecked now if they weren't part of the original game.
Merge branch 'team9dev' of https://github.com/dbeckwith/wpi-suite into team9dev