Remove un-necessary code fragments

	* ::Update is an internal method
Update spacing
Add comments
Make sheet ID of 1 the default
Use local methods when we are able to for better encapsulation

	* Integer data types have also been updated to use library
definitions
Update comments
Update data types to use library definitions
Update spacing
General clean up (use predefined data types, method ordering, comments)
Swap argument ordering of coordinate values back to original (x, y, ...)
Finish Update logic in SDL_Gradient class
Rename of gfx/SDL_Gradient to gfx/Gradient
Rename of gui/SDL_Cursor to gui/Cursor
Swap out SDL_Drawable with IDrawable

	* Remove SDL_Drawable and make IDrawable the inherited class
Batch rename of Canvas, Image, Pixel, Line & Rectangle classes

	* Remove SDL_ prefix from file & class name
Batch rename of (SDL_)BitmapFont, Font, Display & MessageBox classes

	* Remove SDL_ prefix from file & class name
Batch rename of SDL_Input & Timer classes

	* Remove SDL_ prefix from file & class name
Re-order folder includes
Rename function al_check_err to al_err & macro AL_ERR to AL_CHECK_ERR
Batch rename of NOMLIB_* debugging / logging macros

	* Old name -> New name:

NOMLIB_LOG -> NOM_LOG_CLASSINFO
NOMLIB_LOG_ERR -> NOM_LOG_ERR
NOMLIB_ASSERT -> NOM_ASSERT
NOMLIB_DUMP_VAR -> NOM_DUMP_VAR
NOMLIB_DEBUG_ALL -> NOMLIB_DEBUG_TRACE

	* New functions / macros:

Logger::classinfo
NOM_LOG_INFO