Membership signup option during event registration

Allow sites to embed a Membership Block in a CiviEvent Online Registration page. This would work in the same way as the optional membership block in CiviContribute online contribution pages.

One possible additional requirement is the ability to validate event fee levels against a membership type / status - since often organizations have different event pricing for members and non-members. This "validation" would need to work for both existing memberships and memberships that are being "signed up for / paid for" during the event registration sequence.