delete grid directory

This is just a possible reorganization of the contents of this repo.

The entire `grid` directory has been moved to a separate repository,
[gerbaudo/susynt-submit](https://github.com/gerbaudo/susynt-submit)
This seems more natural since in the past we were already doing a
`svn co SusyCommon/trunk/grid`
to create the area from which the jobs will be submitted.
The history of the subdirectory has been preserved using the commands below (see example at [1])

```
git clone git@github.com:gerbaudo/SusyCommon.git
cd SusyCommon/
git remote rm origin
git filter-branch --tag-name-filter cat --subdirectory-filter grid -- --all
git remote add origin git@github.com:gerbaudo/susynt-submit.git
git push -u origin master
```

[1]: http://gbayer.com/development/moving-files-from-one-git-repository-to-another-preserving-history/