First pass at prezto configs
Squashed 'prezto/prezto-install/' content from commit bf9dbfd

git-subtree-dir: prezto/prezto-install
git-subtree-split: bf9dbfd5b95c44b14a8a6af8ecf965ecea50fb29
Merge commit '7a4f85dd319bdaa371699df04c67ea55d6e53ace' as 'prezto/prezto-install'