Allow completion for aliased commands
Allow completion for aliased commands

Before this fix, things like `gco mast<TAB>` would only use filename
completion. This fix will allow the `gco` alias to be expanded and the
autocompletion for checkout  (e.g. branch names) will work as expected.

http://stackoverflow.com/questions/14307086/tab-completion-for-aliased-sub-commands-in-zsh-alias-gco-git-checkout

mattdodge/dotfiles,mattdodge/dotfiles