Parinfer uses `evil-define-key' without loading evil. This means that if
evil is installed *after* parinfer, parinfer will throw up void-function
errors, because evil-define-key (a macro) wasn't expanded at
compile-time.
So we make extra sure evil is installed before parinfer (or at least,
make sure evil-define-key is autoloaded at install time, in case evil
was installed in another session).