Nckw new logger

[nucleosynthesis]

Minimial version of CombineLogger written.
Replaces Logger with stripped down version (CombineLogger)

[nucleosynthesis]

Currently, the log file name defaults to the previous combine_logger.out but functionality is there to specify a name. This needs to be done here : https://github.com/cms-analysis/HiggsAnalysis-CombinedLimit/blob/nckw_new_Logger/bin/combine.cpp#L55 , however the code is structured so that string components that make up the ROOT file name are created much later so formatting the same as the file name would require some restructuring.

[nucleosynthesis]

I think there's a lot of good progress here so I'd be in favour of merging and then we can make more improvements down the road @giacomoortona ?

[giacomoortona]

Agree