Fixes/improvements to ATLASpix timing analysis
This MR cleans up the AnalysisTimingATLASpix module + adds more histograms for an in-depth analysis of low ToT events.
It also contains a fix which is needed for the row and timewalk correction to find the appropriate TGraphErrors.
In addition, it adds the time_offset parameter from the geometry file to pixel timestamps in the EventLoaderATLASpix as it is implemented in the EventLoaderEUDAQ2.
Edited by Jens Kroeger