* This fix is necessary because usually uORB structs get initialized with
all zeros and then get filled with the fields that are actually in use.
* The number 0 for the mode slot was already commanding to switch to the
mode in slot one even though for example the joystick input via mavlink
does not use this mechanism at all.
Filter gets unstable if cutoff is above sample rate/2.
Filter initial frequencies do not matter a lot because they get replaced by parameters anyways.
Filter delay values get reset to 0 when the filter is reconfigured otherwise there can be some weird spikes in the output.
Filter output gets constrained to the range again because of possible overshoot.
Daniel Agar