Add infrastructure for doing compatibility shims, as has been sorely
needed for the last 10 years.  Far too much of the internal API is
exposed, and every small adjustment causes applications to stop working.
To kick this off, bump the API version to 0x17 as should have been done
with r246713, but add shims to compensate.  Thanks to the shims, there
should be no visible change in application behavior.

I have plans to do a significant overhaul of the API to harnen it for
the future, but until then, I welcome others to add shims for older
versions of the API.

Obtained from:	Netflix
The fix committed in r250951 replaced the reported panic with a deadlock... gold
star for me. EVENTHANDLER_DEREGISTER() attempts to acquire the lock which is
held by the event handler framework while executing event handler functions,
leading to deadlock.

Move EVENTHANDLER_DEREGISTER() to alq_load_handler() and thus deregister the ALQ
shutdown_pre_sync handler at module unload time, which takes care of the
originally reported panic and fixes the deadlock introduced in r250951.

Reported by:	Luiz Otavio O Souza
MFC after:	3 days
X-MFC with:	250951
Update dialog to 1.2-20130523
This is an addendum to r251837.
Missed adding the new references to cam_compat.c to the various makefiles.

Obtained from:	Netflix
Update dialog to 1.2-20130523
Level up WARNS