1) fix some problems with the SINEC H1 dissector;
2) make it easier to plug in other dissectors atop OSI transport
protocols (by making the H1 dissector return an indication of
whether it recognizes the packet as an H1 packet or not, so
that, if it doesn't, additional dissectors can be tried).
svn path=/trunk/; revision=1895
and have dissectors for protocols that run at the OSI network layer
register themselves with it using "dissector_add()".
Make various dissectors static if they can be, and remove from header
files declarations of those dissectors.
svn path=/trunk/; revision=1873
