Reworked internal anisotropic filtering code to be more concise and intuitive

src/modules/graphics/opengl/Font.h

@@ -129,9 +129,6 @@ public:
 	void setFilter(const Image::Filter &f);
 	const Image::Filter &getFilter();
 
-	void setAnisotropy(float anisotropy);
-	float getAnisotropy() const;
-
 	// Implements Volatile.
 	bool loadVolatile();
 	void unloadVolatile();
@@ -186,8 +183,6 @@ 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;