Clean up the code just a bit.
Fix the -e option; minor code shuffle
Copyedit option descriptions
Allow "option User" to be specified more than once.
Fix 'option Email'

Need to define email_status even if the option isn't
enabled, so split this into a lib/email.sh that defines
the function and is always available and a separate
option that enables it.

TODO: make the function in lib/email.sh a bare stub and
define the real function in option/Email

TODO: consider more generic ways to handle progress logging
so that users can extend this to use other mechanisms.
Allow "option User" to be specified multiple times