Replacing PR#5954: Threadsafe faster hcal25ns reco method2

 A new PR. This is the SAME as the latest update of the PR#5954 and meant to replace that (with a fresh pull request...)

(ref: PR#5954: https://github.com/cms-sw/cmssw/pull/5954)
shouldn't this be 2 (or, was the name of the function supposed to be Method1)?
Please also add a function to set method 1.