load prezto functions on plugin load
add check for pmodload, fallback to sourcing if it is not defined
Simplify loading prezto plugins with pmodload.
Typo in command in README. Fix #45.
Set `$ZSH` to oh-my-zsh clone location in `-lib`. Fix #46.

Some plugins seem to rely on the `$ZSH` variable pointing to the oh-my-zsh clone
being used. See README for more.
Point autoenv example to my fork.
Add link to the examples page to README.
Fix README: bashrc -> zshrc
Modified some conditional expressions (with DeMorgan's Law) to fix syntax errors on some shells
Merge branch 'fix_relative_path'