Replaced native cursors with skinnable ones.
- Added support for both the new (2013+) and old cursor styles.  These can be toggled on/off in the configuration file.
- Added cursor images by XinCrin (old style) and teinecthel (new style).

Other changes:
- Refactoring: Created a "Utils" module, containing methods and constants that didn't belong in the "Options" state and some duplicated drawing methods.
- Mouse is now grabbed during gameplay.
- Removed 'optionsChanged' switch, simplifying adding new options.

Signed-off-by: Jeffrey Han <itdelatrisu@gmail.com>