vim: a few preference updates
Revert "vim: remove function comment macro"

This reverts commit 7ecea0fe8624bd4a6a6300ebdd934e9e292b1826.
tmux: xterm vs screen
zsh: homebrew python moved
zsh: load zsh-completions if present
vim: go style
weechat: initial/default
weechat: add plugins
weechat: update configs
setup: link weechat
tmux: update some env vars when attaching