don't dissect attributes if there aren't any;
put each attribute into a subtree;
register the dissector by name.
Use "match_strval()" to check whether the message type is a known STUN
message type, and to generate the message type for the Info column.
Don't use "tvb_bytes_exist()" to check when we run out of data - use the
length fields from the packet. Check the sanity of those lengths, too.
svn path=/trunk/; revision=13063
Also move ncp222.py, x11-fields, process-x11-fields.pl,
make-reg-dotc, and make-reg-dotc.py.
Adjust #include lines in files that include packet-*.h
files.
svn path=/trunk/; revision=11410