(ispell-message): Stop if ispell-region returns nil.

(ispell-message): Stop if ispell-region returns nil.
(ispell-next, ispell-word): Catch ispell-quit, not quit.
(ispell-next): Return t if exit normally (no throw to ispell-quit).
(ispell-command-loop): For q, throw to ispell-quit.
Explicitly handle C-g.
(ispell): If we don't call ispell-next, return t.

(ispell-non-empty-string): New function.
(ispell-message): Add autoload.
Choose a citation regexp automatically.
Don't fail if there is no following cited line after filled lines.