add implemenation of IPrAddUTHitsTool which does not do anything

Gerhard Ravenrequested to merge
ingore-ut-hist-tool into master

'bound' tools (which are obtained through operator() by reference) can not be disabled. Hence it is useful to have an implementation of the IPrAddUTHitsTool interface which does absolutely nothing instead...

(also see gaudi/Gaudi#214)

Edited by Gerhard Raven

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