the solution is to introduce a superinterface
and let Dispatcher augment that with the specific parts.
This way, the Job planning only has to rely on the
rather generic stuff (TimeAnchor, FrameCoord)
NOTE: this commit makes the whole JobPlanning machinery
compilable for the first time!
also touches the question how to represent the job
descriptor datastructure. @Cehteh: I've just pasted
in your preliminary data struct definitinons
from the relevant mailing list discussions.
