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

src/modules/graphics/opengl/Canvas.h

@@ -72,6 +72,9 @@ public:
 	void setWrap(const Image::Wrap &w);
 	Image::Wrap getWrap() const;
 
+	void setAnisotropy(float anisotropy);
+	float getAnisotropy() const;
+
 	int getWidth();
 	int getHeight();
 
@@ -119,6 +122,7 @@ private:
 	{
 		Image::Filter filter;
 		Image::Wrap   wrap;
+		float anisotropy;
 	} settings;
 
 	void drawv(const Matrix &t, const vertex *v) const;