* Fix line shader when running under the core profile and make version match those elsewhere.
* Make surface format version match the openGL functions we are using.
Profiling revealed that memcpy() in QOpenGLBuffer::allocate() had been taking
the most time during paintGL() calls. I've been able to take the CPU usage
down to about 1/4 of its previous values by caching elements in VBOs and
updating them only after subsequent calls to renderGraphicElement().
Signed-off-by: Mateusz Zalega <mateusz@appliedsourcery.com>
