acroot_dump: Make --dump-highlevel option work together with --dump-all-events
Let consumers split the ACQt file list as well.

This allows them to notice that the file list associated with their
reader task is actually empty and exit early.
MPI: Bugfix: Do not exit early from ReadFileList.

There was a bug when a subset of the readers did not get any ACQt files
to process.

The bug was caused by the fact that all readers need to participate in
the call to GetTotalNumberOfEntries and GetTotalNumberOfFiles. Otherwise
the readers with files will hang in MPI library functions forever.

Also fixed another possible bug due to the fact that consumers did not
split the file list. For this fix to work it's vital that programs exit
when the ReadFileList function returns false. I fixed the only program
in dev which did not already contain that safety check.
MPI: Move CheckProcessedEvents() to destructor.

Reason: All consumer processeses (+master) have to participate, no
matter if they ever entered in the event loop or not.
MPI: Documentation fix in comment.
Merge remote-tracking branch 'origin/acroot_dumpAll' into dev