Multiplying the transforms while traversing the scenegraph happens now in the right order. The current transform is multiplied before calling functions. #166 + Refactoring
Lights do inherit from group class now, instead of node class. #166
Adds a light proxy, which represents one light in the scene graph. #142
Changes the necessary behavior of the lights after adding the lightproxy. #142
Adds a widgetbuilder for the lights.
Fixes the used representation of lights (lightproxy) for the prerendervisitor. #142
Merge branch 'lighting/managing_lights' of https://github.com/hpicgs/cgsee into lighting/managing_lights