Add FindGLM module and added the respecting FIND_PACKAGE to CMakeLists
Fixed the latest GLM breaking things

The latest GLM removes some implicit casting to glm::vec3 so it is now explicitly done.
Also glm::mul() is no longer available so changed line 666 in OpenGLSystem to use the * operator instead.

Also added a missing include to <iostream> in GLCubeSpehre.
Merge branch 'develop' into vcomputer