removed the tick() function, and replaced the invoking code with
direct calls to update().
fixed a bug, where the low shelf bandwidth was getting the incorrect data.
analyser now disabled when not in view.
band vu meters now disable when analyser is disabled.
display nema changed to Equalizer.
set sample rate before frequency on LinkWitzRiley filters.
Grouped the setting of filterparameters into one function, and calc coefficent
once if needed.
Made suitable function inline.
in and out vu meters now using both stereo channels
Dave French