Changes to the Update function

The Update function is not likely to ever be called inside our game. Emscripten's dead code removal process should eliminate it. However, we haven't removed it from the Emitter class. If you think you may ever call this, you might want to change the m_min_angle and m_max_angle initialization to convert from degrees into radians, like we did in the constructor:

m_min_angle = (min_angle+90) / 180 * 3.14159;
m_max_angle = (max_angle+90) / 180 * 3.14159;