Allow messages with zero length bodies

AMQP 1.0 Specification 1.0, section 3.2, Message Format states that:

The body consists of one of the following three choices: one or more data sections, one or more amqp-sequence sections, or a single amqp-value section.

It is felt that this is too restrictive and that messages with zero length bodies should be allowed.

This issue is raised so it is considered for inclusion in AMQP 1.1, should it ever happen.