fixOSXCompatibilityProfileDetection

On OSX the OpenGL profile is reported as no profile, if the required version is not available. This is exactly the case, if we use the compatibility profile with an OpenGL Version higher than 2.1

This change also reports true for isCompatibilityProfile, when no profile is reported, so the fallback context on osx is treated as compatibility profile.

compare discussion in https://www.graphics.rwth-aachen.de:9000/OpenFlipper-Free/OpenFlipper/merge_requests/73