Minor fish prompt tweaks
Add a newline before each prompt for separation
Add AWS private IP lookup function and completion
Add custom Git workflow functions
Force Vim to stay in foreground when editing commit messages

This solves the problem with:

    error: There was a problem with the editor 'vi'.
    Please supply the message using either -m or -F option.

https://stackoverflow.com/questions/22699614/git-commit-messages-lost-by-vi
Force a POSIX compatible shell for internal Vim functions

Using fish means Vim can't find some of the standard POSIX things that
it relies on, so we must override the shell variable that gets picked up
from the environment.
Add function to SSH without using known_hosts protection