Enables the osx module.

Signed-off-by: Markus Hubig <mhubig@gmail.com>
Moves the path settings back to zshenv.

After some discussion with @sorin-ionescu I moved the path settings back to
zshenv where they belonged. I now use a zsh compiled with:

`brew install --disable-etcdir zsh`

Signed-off-by: Markus Hubig <mhubig@gmail.com>