function enterFrame(e) {
                var l = 0;
                for (i in tweens) {
                    var prop = tweens[i];
                    if (prop.remTime > 0) {
                        prop.current += prop.diff;
                        prop.remTime--;
                        Crafty.viewport[i] = Math.floor(prop.current);
                        l++;
                    }
                    else {
                        delete tweens[i];
                    }
                }
                if (l) Crafty.viewport._clamp();
            }
@
#Crafty.viewport.pan
@comp Crafty.viewport
@sign public void Crafty.viewport.pan(String axis, Number v, Number time)
@param String axis - 'x' or 'y'. The axis to move the camera on
@param Number v - the distance to move the camera by
@param Number time - The duration in frames for the entire camera movement

Pans the camera a given number of pixels over a given number of frames