Cherry pick MR !545 to master

Implemented a way to check counters in the tests

Counters were ignored by default. With this commit, you can selectively check them Just call compareCounters(stdout, reference, causes, result, countersToCheck) in the validator part of your qmt test, where countersToCheck is a list of algo names or pairs algo name/list of counters names that should be checked. Not listed algos will not have their counters checked at all. Algos listed with a list of counters will only have these counters check. Example of such a list : countersToCheck = ("createUTLiteClusters", ("ForwardFitterAlgorithm", ("nFitted", "nTracks"))) This will check all counters of createUTLiteClusters and only nFitted and nTracks counters in ForwardFitterAlgorithm

@jonrob FYI, we could use this to replace the painful reference block for checking the ANN PID counters. See usage example in Brunel!132 (diffs)