[.vimrc] Add a command :BR AB, try to replace bracket A as bracket B
[.vimrc] Change background color of inactive tab
[.zshenv] Add check for MacPorts: if you're using MacPorts, ``/opt/bin`` and ``/opt/sbin`` are needed to be added into $PATH
[zsh/completions] Add completion for ``sh`` to filter out something I don't want
Merge branch 'develop_vimrc'
Merge branch 'develop_zshenv'