Fix unnormalized interpolated normals

Interpolated normals are typically not unit length and need to
be renormalized in the fragment shader. This change adds
normalization for normals that are passed through the vertex shader
and therefore interpolated. This change replaces a number of valid images
that were previously added for OpenGL2 due to Phong lighting changes and
it adds a number of new images due to the phong lighting change that
are now showing up. Almost all the cases involve rendering low resolution
spheres and cylinders, both of which come with normals in VTK and for which
phong lighting can make a big difference.

Change-Id: Iab60742b5684f3e7a6575b28ad23e10572c9e67d
Merge topic 'fix_normals' into master

34a8a2d2 Fix unnormalized interpolated normals