opengl 3.3 renderer integration, minor renderer tweaks

sun.h

@@ -23,7 +23,7 @@ public:
 	// returns vector pointing at the sun
 	glm::vec3 getDirection();
 	// returns current elevation above horizon
-	float getAngle();
+	float getAngle() const;
     // return current hour angle
     double getHourAngle() const;
     // returns current intensity of the sun