Enabled this script to be usable even when the user is not 'git'

GitHub functions under the assumption that the repos are always
managed by the system user 'git', whereas there are some repos that
don't respect this convention. I've added a workaround for those
cases.

Also, turned the shebang to Bourne from Bash as not every system has
Bash installed by default.
Change other scripts to use sh for consistency
Merge branch 'dotemacs-not-only-github'

* dotemacs-not-only-github:
  Change other scripts to use sh for consistency
  Enabled this script to be usable even when the user is not 'git'