fixed hadd issue

I am just going to open and close this issue for posterity.

Problem:

Couldn't hadd histograms in the Correlations folder.

Solution:

Removed ':' from the folder name.

As a "DAQ expert" who tried name files with '/' it might not be immediately obvious that ROOT doesn't like it if folder have ':' in their names.

Maybe moving forward we removed whitespaces from folder and histogram names. Makes it easier to user in ROOT.