Description for ProcessEvents has changed in SAPPHiRE

Currently only in a branch of SAPPHiRE
When it is merged, this should also be merged to master
Merge pull request #49 from HiSPARC/trigger_timings

Description for ProcessEvents has changed in SAPPHiRE branch trigger-timings.
It is now a dict (processed_events_description) in the ProcessEvents class.