Add package mo-git-blame from MELPA

Sometimes you want to know where things came from.
Configure mo-git-blame package

at least, I tried to. It doesn't seem to respect the variable in question.
Turn on auto-fill-mode in Unix config files

also in .git{config,ignore} files.
Extend (and document) .gitignore

Because a clean git status is a good thing.
Remove .gitignore entry for old-style Jedi virtualenv