brew: order formulae by name
st3: remove toggle minimap plugin
add warning about brew/clamxav conflict
fixes for setup scripts

- use message functions from `lib/utils.zsh` where appropriate
- use `source` instead of `.`, as suggested by @christianbundy in #1
  (thus likely setting myself for a merge conflict upon pulling :P)
- revise `seek_confirmation` to allow for output when `stderr` is being
  redirected
- spacing, formatting, etc.
remove bin/todo
todo update
readme: add note about what the hell is homebrew