text: Title: Examples fail to run, aborting with a raised "Unknown GLSL error format"
  Body: I tried a few examples, including https://github.com/glumpy/glumpy/blob/master/examples/gloo-antialias.py and they fail with the following error. I have just noticed that glxinfo is showing that direct rendering is not working. I am not sure if that is causing the problem.
  
  python main.py
  [i] Using GLFW (GL 4.4)
  [i] Running at 60 frames/second
  Traceback (most recent call last):
    File "main.py", line 64, in <module>
      app.run()
    File "/usr/local/lib/python2.7/dist-packages/glumpy/app/**init**.py", line 301, in run
      clock = **init**(clock=clock, framerate=framerate, backend=**backend**)
    File "/usr/local/lib/python2.7/dist-packages/glumpy/app/**init**.py", line 261, in **init**
      window.dispatch_event('on_resize', window._width, window._height)
    File "/usr/local/lib/python2.7/dist-packages/glumpy/app/window/event.py", line 375, in dispatch_event
      if getattr(self, event_type)(_args):
    File "/usr/local/lib/python2.7/dist-packages/glumpy/app/window/window.py", line 197, in on_resize
      self.dispatch_event('on_draw', 0.0)
    File "/usr/local/lib/python2.7/dist-packages/glumpy/app/window/event.py", line 365, in dispatch_event
      if handler(_args):
    File "main.py", line 18, in on_draw
      program.draw(gl.GL_POINTS)
    File "/usr/local/lib/python2.7/dist-packages/glumpy/gloo/program.py", line 499, in draw
      self.activate()
    File "/usr/local/lib/python2.7/dist-packages/glumpy/gloo/globject.py", line 87, in activate
      self._create()
    File "/usr/local/lib/python2.7/dist-packages/glumpy/gloo/program.py", line 147, in _create
      self._build_shaders(self._handle)
    File "/usr/local/lib/python2.7/dist-packages/glumpy/gloo/program.py", line 195, in _build_shaders
      shader.activate()
    File "/usr/local/lib/python2.7/dist-packages/glumpy/gloo/globject.py", line 97, in activate
      self._update()
    File "/usr/local/lib/python2.7/dist-packages/glumpy/gloo/shader.py", line 205, in _update
      lineno, mesg = self._parse_error(error)
    File "/usr/local/lib/python2.7/dist-packages/glumpy/gloo/shader.py", line 242, in _parse_error
      raise ValueError('Unknown GLSL error format')
  ValueError: Unknown GLSL error format
  
  Compilation exited abnormally with code 1 at Mon Aug 31 15:14:35
  