added registration to lvl1 controllers

added lvl1 controller interface (+ template for buffer swapping)
added lvl0 controller interfaces
added controlmodes namespace + default control modes
all data units now are splitted into an interface (this has to be implemented) and a ptrprovider (this is a conveniene class. it stores pointer and implements the interface. if all data is already somewhere in ram, you can set the pointers of this class and have a working data unit)

they pass all data they receive to configurable callbacks

Previously the error only appears if the current value remains zero over a period of time.