Tiled 0.5.0

• Added support for import and export plugins
• Added support for external tilesets
• Added undo for adding tilesets and ability to remove tilesets
• Added error handling to the New Tileset dialog
• Added ability to change tileset order by dragging them around
• Added option to draw the tile grid when saving as image
• Added a context menu and tool buttons to the layer dock
• Added Latvian translation
• Added an install target to the Makefile
• Open local files when they are dropped onto Tiled
• Allow changing position and size of objects in the Object Properties dialog
• Fixed rendering issues with tiles wider than the tile width of the map
• Fixed eraser and fill tool working on invisible layers
• Fixed a crash when using some tools when no map is loaded
• Fixed compile errors related to detecting static builds
• Fixed the Save dialog not suggesting any particular file extension
• Updated Japanese, Dutch, German, Brazilian Portuguese, French, Portuguese and Spanish translations