separated ZH channels

Hi @mverzetti ,

I've made some changes to the Makefile so that it will run expected limits on the llt, ltt, llll, lllt, lltt, and zh (combined) channels separately on the latest 8 TeV input shapes in CVS. I didn't add this for 7 TeV yet since, last I checked, the datacards were not altogether updated yet anyway.

To get it to work you'll have to add the extra zh channels to the setup. I've made a PR for this as well, but you can see that the change is very minimal anyway:

https://github.com/cms-analysis/HiggsAnalysis-HiggsToTauTau/pull/44

I'm currently working on updating to run separated pulls as well.

Stephane