Version 0.5.0

• Significant code refactor and fixes by @ali1234
• Metadata dump fixed to support RL images
• Bugfix to incorrect transparent colour being selected
• Configurable empty_tile for .tmx maps - specifies a tile ID for unset/empty tiles to be remapped to
• Optional struct output type for .tmx maps with width, height layer count and empty_tile
• .tmx map layers are now sorted
• Should not break compatibility, but use 0.4.x if you don't need the new features