[Clas12_software] EVIO ROOT tools

[Gagik Gavalian]

Dear Clas12 software enthusiasts,

I have finished implementing ROOT/CINT tools for browsing/reading evio files directly from
root. Current version mimics ROOT native Tree object, which makes it possible to interact
with the evio file in a same manner as with a ROOT file. User can browse and make plots 
with just clicking on the Tree branches, apply cuts and selections.

There are also supporting methods to use the tree in the CINT script for analysis, and checks.

The documentation for this project is located at:

https://userweb.jlab.org/~gavalian/clas12docs/sphinx/html/rootio/introduction.html

Any comment and feedback is appreciated.

Gagik