Log Message:
Import git-sh-1.3 as shells/git-sh.

git-sh is a customized bash shell suitable for git work.

The git-sh command starts an interactive bash shell tweaked for
heavy git interaction:

* All git commands available at top-level (checkout master = git
  checkout master)
* All git aliases defined in the [alias] section of ~/.gitconfig
  available at top-level.
* Shawn O. Pearce's excellent bash completion strapped onto all
  core commands and git aliases.
* Custom prompt with current branch, repository, and work tree
  dirty indicator.
* Customizable via /etc/gitshrc and ~/.gitshrc config files; for
  creating aliases, changing the prompt, etc.
* Runs on top of normal bash (~/.bashrc) and readline (~/.inputrc)
  configurations.