Merging 'Histogram/Tools' and 'Histogram/Analysis' subpackages

* PlotCollection class now renamed to HistogramCollection and moved to 'Histogram/Analysis' subpackage
* PlotFwd.h also moved
First commit of this example

Example executable that shows how to use the class Histogram collection
Code moved to header file
Moved implementaion to header file and added methods

* Moved all methods implementation to the header file in order to allow on the fly compilation for new classes using the template.
* Implemented method for setting line color