Add a link to the page about the git repo from the main 'software' page.
Add a link to the page about the git repo from the main 'software'
page.

Also, remove the 'NEW!' icon from the 5.0 release, which is now about
18 months old.

nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome