Gcc110fix

1. allow dependency build of OpenCSG even if qmake is not present

2. change Cmake to detect GLU in our own built-dependencies

this is not perfect but it will make gcc110 work, and provide a nice little foundation for other systems in the future that lack QT and/or GLU. (GLU as you know has been split out from GL in some future linux distros)

the main thing 'not done' is to auto-detect whether GLU needs to be built... (currently i use the very crude method of assuming that if we dont have qmake, then we need to build it before building opencsg)