Added support for DXT1/3/5 and BC5/7 compressed textures via love.image.CompressedData. Some internals are still iffy.

- added a new CompressedData type to love.image
- added love.image.isCompressed(file or data)
- love.graphics.newImage automatically tests for compression when loading a file
- added love.graphics.isSupported strings for DXT, BC5, and BC7

Compressed textures meant to be used on the GPU offer huge performance gains when
- loading the texture from a file
- loading the texture from RAM to VRAM
- loading mipmaps
- rendering

--HG--
branch : image-CompressedData

src/modules/image/Image.h

@@ -26,6 +26,7 @@
 #include "common/Module.h"
 #include "filesystem/File.h"
 #include "ImageData.h"
+#include "CompressedData.h"
 
 namespace love
 {
@@ -77,6 +78,26 @@ public:
 	 **/
 	virtual ImageData *newImageData(int width, int height, void *data) = 0;
 
+	/**
+	 *
+	 **/
+	virtual CompressedData *newCompressedData(love::filesystem::File *file) = 0;
+
+	/**
+	 *
+	 **/
+	virtual CompressedData *newCompressedData(Data *data) = 0;
+
+	/**
+	 *
+	 **/
+	virtual bool isCompressed(love::filesystem::File *file) = 0;
+
+	/**
+	 *
+	 **/
+	virtual bool isCompressed(Data *data) = 0;
+
 }; // Image
 
 } // image