Python 3 Support

Installation
8

Sweet!

Panda3DExamples $ cd asteroids/
asteroids $ pwd
/Users/jkuhl/Projects/LearnPanda3D/Panda3DExamples/asteroids
asteroids $ python3 ./main.py
Known pipe types:
  CocoaGraphicsPipe
(all display modules loaded.)
asteroids $ python3 --version
Python 3.6.0
asteroids $

I just loaded up a copy of Asteroids and it worked ok. A quick test of some of the other examples also worked. Very happy.

Thank you!