Email address with leading or trailing space is not accepted by web subscribe.

[Mark Sapiro]

If an address is entered on the web listinfo subscribe form with a leading or trailing space, it is rejected with the message "The email address you supplied is not valid. (E.g. it must contain an '@'.)". This is confusing to the user who looks at the address and sees it does contain an '@' and appears valid.

Leading and trailing whitespace should be stripped from the address entry.