Removed all uses of deprecated NSOpenGLPFACompliant

Apple's docs say about this constant:
"effects should be considered undefined, and their use avoided"

"Undefined" is pretty stern discouragement!

Now vtkCocoaRenderWindow::SupportsOpenGL() returns true
simply if an OpenGL context exists.

Change-Id: I20d52fb747241e08ea732ed554b3462c461623ee
Merge topic 'NSOpenGLPFACompliant' into master

468f25df Removed all uses of deprecated NSOpenGLPFACompliant