Use underscore separator when specifying module implementation
Victor Krylov's suggestion (it is reasonable, to avoid confusion in the future):
instead of having TpcClusterHitFinderMlem & TpcClusterHitFinderFast to change to
TpcClusterHitFinder_Mlem & TpcClusterHitFinder_Fast
and make appropriate change in naming rules document on the website
Edited by Slavomir Hnatic