Moved anisotropic filtering to Image:setFilter(min, mag, anisotropy), added anisotropic filtering support to canvases and fonts

src/modules/graphics/opengl/Font.h

@@ -129,6 +129,9 @@ public:
 	void setFilter(const Image::Filter &f);
 	const Image::Filter &getFilter();
 
+	void setAnisotropy(float anisotropy);
+	float getAnisotropy() const;
+
 	// Implements Volatile.
 	bool loadVolatile();
 	void unloadVolatile();
@@ -183,6 +186,8 @@ private:
 	float lineHeight;
 	float mSpacing; // modifies the spacing by multiplying it with this value
 
+	float anisotropy;
+
 	int texture_size_index;
 	int texture_width;
 	int texture_height;