templated value type of input branch in BinnedKernelDensity and AdaptiveKernelDensity

Hi Anton, here is a small modification that we use in the LcD0K analysis.
It's for being able to use different types of branches and avoids errors like

Error in <TTree::SetBranchAddress>: The pointer type given "Float_t" (5) does not correspond to the type needed "Double_t" (8) by the branch: mLb

I hope you find it useful. Cheers, Marian