[Fix #516] Define ZLE functions separately
[Fix #522] Do not load the terminal module in non-graphical terminals
Fix setting the 'pac' alias
Merge branch 'master' of https://github.com/sorin-ionescu/prezto
[Fix #535] Set Pacman frontend to 'pacman' when none set
Merge branch 'master' of https://github.com/sorin-ionescu/prezto