Indentation fixes.
Moved default state checking to the top of InitializeScenes().
Added a text field UI element. Added base options menu. Even more misc. changes.

* TextField.cs, UIElement.cs, Options.cs, OptionsScene.cs:
  Initial version.

* ParameterAttribute.cs:
  Updated documentation.

* Input.cs:
  Added KeyPressed, MousePressed, and TextEntered events.
  Renamed regions.

* Program.cs:
  Enabled key repeat.
  Now reads options and parsing them for parameters.

* MenuScene.cs:
  Refactored CreateButtons() method and added an options button.

* ButtonList.cs:
  Added Scrolled event.
  Removed explicit destructor since the class will usually go out of
  scope at the same time the parent scene will. Will look into more
  later.
  Added GetClosestIndex() method.
  Added _SetIndex() method.
  Updated the way scrolling is handled.

* Extensions.cs:
  Added Position() method.
  Added Right() method.
  Added MakeFirstUpper() method.