Debug Menu Support

• Added a "Debug Menu" to provide run-time data tweaking.

` or ~ (backtick or tilde) to activate or deactivate.

Once activated the Debug Menu takes the input focus away from the main game.

Navigate the Debug Menu via the arrow keys... up/down to select items, left/right to modify the current selection.

• Provided the following functionality via the Debug Menu

• Frame rate monitor (via 'Text' widget)

Adjust fly-cam speed (via 'Slider' widget)

Reset fly-cam back to the origin (via 'Button' widget)

• Added debug shape drawing

Line

Box

Sphere

• The Debug Menu and debug shapes will completely vanish from your code in a release build.