Fix issue with mesa and gl_FrontFacing

This fix seems to work on both Mac and Mesa. It should be good
on all other platforms as well. Also did some indentation cleanup.
The only real change was changing

  if (int(gl_FrontFacing) == 0)

to

  if (gl_FrontFacing == false)

Change-Id: If4270f1a87ae495445dffd8af72fee1bfa0f2011
Merge topic 'mesa_lighting_fix' into master

221ba52d Fix issue with mesa and gl_FrontFacing