[Halla12_software] SoLID GEMC simulation version control

[Zhiwen Zhao]

Hi, folks

For the concern to have tracked back history of our SoLID GEMC 
simulation respect to GEMC update, we should be more careful about 
version control.

I update the page of "Solid install" with more up2date information.
https://hallaweb.jlab.org/wiki/index.php/Solid_install
and also made a new page for version history.
https://hallaweb.jlab.org/wiki/index.php/Solid_GEMC_version_historty

later any new production version shall be announced on the wiki and this 
emaillist.

let me know any question.

Thanks

Zhiwen