awesome: redo everything

Mostly from nathan7's config:

https://github.com/nathan7/awesomesauce
zsh: extract env vars to ~/.environ

This allows them to by sourced by other places -- such as ~/.profile --
and be included in X's env.
fix(mx): only match exact matches for existing sessions
feat(aliases): add bundle install alias
fix(zshrc): always put .bundle/binstubs at the front of PATH