Make the protocol ID argument to "dissect_transform()" an "int", and

Make the protocol ID argument to "dissect_transform()" an "int", and
pass -1 in the cases where it's not called from "dissect_proposal()",
i.e. where there *is* no protocol ID to pass it, and have it dissect
the transform ID only as a number if the protocol ID isn't one of the
ones we know about.

Give the payload dissectors other than "dissect_transform()" an extra
"int" argument, so that their signature is the same as that of
"dissect_transform()", put "dissect_transform()" back in the
"strfuncs[]" table, and get rid of the special-casing of
"dissect_transform()" in "dissect_payloads()".

svn path=/trunk/; revision=4086