Added git mode support for merging, rebasing, and bisecting

<B> Designates Bisecting
>M< Designates Merging
>R> Designates Rebasing
Merge pull request #2633 from redsunsoft/agnoster-theme-git-mode-addition

Added git support for merging, rebasing, and bisecting to agnoster theme
git: don't alias gm to git merge; conflicts with GraphicsMagick
add the ondra theme
ls: color more audio files
automate my two-branch upgrades