Edit different states

I'm seeking for something to edit quickly changes. After see your cool [screencast](http://www.youtube.com/watch?v=NmxZczuN7_8) about Gapply I started a fork about editing other interesting states

By now changes is only an extension to deal with:

- git diff (original support)
- git diff --cached
- git show

Of course saving doesn't work yet, but it's something about play with git reset, git checkout, and git apply

Evenmore, given that I want to allow destructive changes (edit git show) I planned some backup files, as *.orig performs after a merge

So any situation which solution is clear to you, just let me know.

I think better aproach is to create a branch and share commits from both sides (you and me, I mean) If that workflow sounds good for you I will rework this.