Use div tags instead of P, for BBcode compatibility

Because BBCodes may introduce div tags and other tags not valid inside of P tags, we should replace the use of P tags with DIV tags instead for the output of the message content..
It's inline because it is unique to this one and only location, and should not require a whole CSS include process just to enforce a couple style attributes to look right for our purpose here. There is inline styling here anyways because the background color depends of template variables from the current bgcolor entered.