StdDataGatherer: an option to gather for a given time duration
gatherDuration [us]
sets up DataGatherer to collect the data for the
given duration, without relying on the trigger loop.
It is needed in the case of gathering external triggers, such as TTC from ALTI.
modified: src/libYarr/StdDataGatherer.cpp
modified: src/libYarr/include/StdDataGatherer.h