[Halld-offline] subversion to git conversion started

[Mark Ito]

Fplks,

The process has started. It will take several hours. The practice 
repositories for hdds and sim-recon have been deleted on GitHub. I'll 
let you know when the GitHub repositories are ready for use.

Again let me remind you that the subversion repository is unaffected by 
this process. The only difference is that we now view the subversion 
hdds and sim-recon directories as non-authoritative.

   -- Mark