Added GIT_EDITOR env var and set to mvim.
Added GIT_EDITOR env var and set to mvim.

Git will look at the EDITOR env variable to determine which editor to
use for commit messages. However, that is the last place that it looks,
so I decided to add back the GIT_EDITOR env variable to .bash_profile,
since that is the first place git will look.

matthewrankin/dotfiles,matthewrankin/dotfiles