The automatic selections of the measured quantity and equivalent circuit
model are more part of the configuration of the meter than attributes
of the measurement result. To reflect this, model them as config keys
instead of mqflags. This allows a driver that supports remote control to
implement 'set' method for them and has the additional benefit of saveing
two flag bits.
This returned an array of structs with an NULL-ed element at the end.
The drivers still do this, but the wrappers now make and free a NULL-
terminated array around it.
sr_output_options_free() now takes the pointer returned by
sr_output_options_get(), instead of the module owning it.
Output modules are now guaranteed:
- Every option is always given, with the default value if not supplied
by the user, and is the right GVariantType.
- No invalid options are ever passed.
Audio tools processing WAV failes generally need the samples to be in
the range -1 to +1. The scale option adds postprocessing to any samples
going into a WAV file, by dividing the sample values by the given factor.