Added transparent rendering of images
Removed the punchthrough colour, all palette values of 255 are transparent

|SOURCE|
[Image]
* Added DrawTransparent and DrawSubTransparent to allow for rendering images
  with transparent pixels
[Video]
* Added FillRasterLineTransparentOffset and FillRasterLineTranspaentXY, which
  will draw all pixels not marked as transparent
[Main]
* Fixed the height and bearing of the 'n' character, which had one pixel too
  many
* Using the IMG_DrawTransparent to display the new transparency capabilities
[Text]
* IMG_DrawSubTransparent is used to display fonts with transparency correctly