Add new mesh data formats: int32, uint32, [u]int8, [u]int16, snorm8, and snorm16.

Integer formats for vertex attributes are only supported in glsl3 shaders. They use ivec/uvec types in glsl.

--HG--
branch : minor

src/modules/graphics/Mesh.h

@@ -187,7 +187,7 @@ private:
 	};
 
 	void setupAttachedAttributes();
-	void calculateAttributeSizes();
+	void calculateAttributeSizes(Graphics *gfx);
 	size_t getAttributeOffset(size_t attribindex) const;
 
 	std::vector<AttribFormat> vertexFormat;