Bruce's idea: the default Histogrammer behavior = the current one,
LoopStatus is by default end_of_iteration, set it to false to make the
histogrammer accumulate multiple FrontEndData from 1 scan iteration.

	modified:   src/libYarr/HistogramAlgorithm.cpp
	modified:   src/libYarr/StdDataLoop.cpp
	modified:   src/libYarr/StdDataLoopFeedback.cpp
	modified:   src/libYarr/include/LoopStatus.h
	modified:   src/libYarr/tests/test_histogrammer.cpp
	modified:   src/libYarr/tests/test_hits_per_event.cpp
	modified:   src/libYarr/tests/test_l13d.cpp
	modified:   src/libYarr/tests/test_l1dist.cpp
	modified:   src/libYarr/tests/test_occupancy.cpp
	modified:   src/libYarr/tests/test_tot3d.cpp
	modified:   src/libYarr/tests/test_tot_dist.cpp