- Prepare gui::layout/gui::base for when they (if they do) need to 'contain' each other; the layout a vector of bases, the base a pointer to its parent layout.
- Added gui window component.
- Base gui asks now for viewport and viewprojmatrix. Will have to ask for the parent layout and parent component at some point in time.
- Created gui helpers file. Will at some point contain GL helper functions.
- Created 'update view' routine for GUI system, for when the window size changes or the engine is initialized.
- gui layout add component now returns a pointer to that component, to allow modification by the user.
- Added runtime files (lua config, and two shaders).