em: fix a typo
cookies: fix up some style
em: add a safe_raw method to Arguments

This prevents '@' from being used to expand a variable.
cookies: use the new cookie command
cookies: use safe raw strings
config: document the '_G' command

Underscores are "special", but only after a <:> block, but this isn't
mentioned anywhere. Indicate that it is not magic here.

Thanks to Bill Evans for pointing it out.