Update completions
Go big or $GOHOME
Remove zsh completions submodule

Will just cherry pick what I need
Simplify tmux workspaces

Most projects have four windows: vim, shell, console, server.

This commit changes `mx` to unfurl that layout for any project,
checking for `script/console`, `script/server` first. Per-project
layouts can be scripted with a .tmux file in the project root.

New usage:

    cd ~/github/<project> && mx

or

    coral cd <project> && mx