Fixes to EventDefinitionM26
This MR contains a few small fixes + clean-up of the new module
EventDefinitionM26 by @lhuth
In addition, it also contains one change to the
EventLoaderEUDAQ2 with respect to how the histograms
clipboardEventStart/End/Duration are filled.
Previously, they've been filled each time a clipboard event was found to be defined. This leads to double-counting.
Now it's only filled, when the event is placed on the clipboard, such that the number of entries is equal the number of processed event (as shown in the terminal or when using
number_of_events). As a side-effect, these histograms are empty for those instantiations of the module that don't place a new event on the clipboard but only read it.