Custom Fps Limiter

First time contributing. Set FPS limit on second page of graphics
settings. Press Tab key or on 360 controller, press left stick to toggle
between 3 states.
Fixed Config saving

Fps limit now saves in configuration. It can also be edited there to
allow for any value of fps.
Allow Tab to Unthrottle
Fix
Add tab to unthrottle
Merge pull request #1739 from makotech222/master

Custom Fps Limiter