- added another row of tiles from zelda tileset for more margin/spacing testing
- removed tilex,y indices
- added a function for calculating u,v,u2,v2 coords with pixel correction
- cleaned up some unused function
- cleaned up some comments
- adjust main.cpp to reflect the changes
- added a way to print the tile coordinates
- no tests adjusted for this yet
- comment
- replicated test_xml_file but with different layers