Get rid of push/pull shortcuts, as they weren't widely used.
Add contents to repo on git init.
Centralize git add logic, and make it less error prone.

Laurent asked for this.

Reported-by: Laurent Ghigonis <laurent@p1sec.com>

A user made this request:

    I was wondering whether it is in a planning to have multiple
    password-store directory trees or possible to achieve? eg.
    $HOME/.pwd-store-work and $HOME/.pwd-store-home. Maybe distinguish them
    with a command line switch and then create aliases in .bash_aliases?

    Why I'm asking is that I have multiple major password categories -
    personal, work etc. It'll be nice to keep them separate and under
    different repos.

Reported-by: Simon KP <si@eskp.net>

This allows users to edit password files using temporary files created
in /dev/shm. This commit also tidies other things up and fixes minor
bugs and griviences that should be separate commits but aren't.

Reported-by: rupa <rupa@lrrr.us>

Add a --no-echo flag to the insert operation so that the password isn't
echoed when entering it. This requires the user to echo the password
twice for confirmation.

Reported-by: Dominic Lüchinger <d.luechinger@snowgarden.ch>