This patch implements OpenGL error checking in VTK.

OpenGL's error handling implementation error is designed such
that internal error flags remain set with the first error that
occurred until they are explicitly checked. With this design
it's important to check and clear the error flags regularly
else they become unusable as code checking for errors ends
up reporting earlier undetected unrelated errors.

This patch takes the following approach:

1) at public entry points into code that uses OpenGL clear the
error flags without reporting errors. This guards against
reportinig unrealted errors, such as those caused by code
outside of VTK. See vtkOpenGLClearErrorMacro

2) before returning from functions that made OpenGL calls check
for and report OpenGL errors. This detects Open GL errors in the
function/method where they occurred facilitating debugging and it
clears error flags so that user code doesn't detect errors caused
by VTK. See vtkOpenGLCheckErrorMacro

This patch cleans up a number of bugs that were detected by
the new error checking and reporting.

This patch also contains improvements for OpenGL pixel buffers, a
renderbuffer object, and fast paths through framebuffer objects,
and texture objects, and fast path for setting uniform variables,
all of which are needed in vtkSurfaceLICPainter and
vtkLineIntegralConvolution2D GPGPU code.

Change-Id: I4ecefe9a444a74128bf73ef2ddfd5d4acea387ec