TODO

* actor creation in a thread
* set_resize is working. correctly inject it into the on_resize event.
* math text/function visualization from sympy with Plot._pobjects
* * group/ungroup of actors
* server with ports open for websocket, running engine and taking commands
* progress bar
* streamable sources, e.g. with pyffmpeg
* slice viewer
* command menu for actors
* scene graph?
* view volume -> yt
* change transparency
* "action" wrapper for objects
* use function overwriting for e.g. draw functions, lighting condition changes
* colormaps. 3d to 1d. e.g. 256 colors, interpolate function inbetween
* labels (network), follow the camera when moving
* movie, ffmpeg
* save screenshot
* options for debug modus of opengl
* graphmenu actor. ortho mode, select options
* nx example working again
* world has a list of windows. (add window removal/close)
* camera logic, e.g. camerapath
* http://3dengine.org