Pete Resnick comment - second try

"6.3.4 - No discussion of wildcard in this section. Does there need to be?"

New text is:

The response to a message sent to a Node-ID MUST have been sent
by that Node-ID, unless it has being sent to the wildcard
Node-ID.
Merge pull request #224 from petithug/pete-resnick-2

Pete Resnick comment - second try