Better smoothing with FBOs

[nasser]

Get rid of code like this

  if(_zj_smoothing == Qtrue && _zj_fill == Qtrue) {
    /*  smoothing is on and the rectangle was filled. draw a smooth outline. */
    ofNoFill();
    ofRect(NUM2DBL(x1), NUM2DBL(y1), NUM2DBL(w), NUM2DBL(h));
    ofFill();

  }

and use FBO multisampling to implement smoothing. render everything to an FBO and then draw that to the window. the smoothing method will control the number of samples in the FBO.

[nasser]

Possible syntax:

smoothing false # sets FBO's samples to 0
smoothing true # sets FBO's samples to maximum i.e. ofFbo::maxSamples()
smoothing 4 # sets FBO's samples to 4
smoothing 5 # sets FBO's samples to 5
smoothing 6 # sets FBO's samples to 6

[nasser]

If this can get in for 0.4.0, that's great. But it shouldn't hold things up.