Enable the trigger and event builder tasks for reading from CbmDigiTimeSlice. Refs #2275.
The up-to-now implemented tasks CbmTaskTriggerDigi and CbmTaskBuildEvents (in reco/tasks) take as input digi vectors as branches of the ROOT tree, which suits input data provided from simulations. In order to connect them to the unpacker and its output, they have to read from CbmDigiTimeSlice. This MR enables them to do so, keeping the possibility to read and process simulated data.
Plus some cleanup in algo/evbuild/EventBuilder.
A macro connecting all three steps (unpacking, triggerring, event building) can be committed after !750 (merged) is merged.
Refs #2275.