Git Kill

@charlierudolph this implements #87 
Same here. Maybe create a function in git_helpers.

```bash
function commit_open_changes {
  run_command "git add -A"
  run_command "git commit -m 'open changes'"
}
```

I also think the commit message should be a bit more specific. 
Maybe something like the git-stash default message:
`WIP on master: 049d078 added the index file`