Standalone json file to control analysis

[hschellman]

Now that analyze gets it's info about the original config from root, we need to (and can add) an analysis config system. this allows you to analyze a subset of the info once we figure out how to do that.
The signal, background and data times in the main config are analysis only and a good first pass.

[smgilligan]

In support of minimizing user input/transposition errors would we want the sidebands code to produce a default analysis configuration file as an output? There are a growing number of items in our configuration files to keep track of, and I've definitely made mistakes copying and manually editing configuration files.