Fix for C343-299, warning on killing tame engulfer.

* C343-299:  Killing tame engulfer from inside gives a warning message.
             Author:  Jared Minch
             Source:  https://github.com/sgrunt/GruntHack/commit/3df702230a3f767a4c7dd6f98d0156ed621a49ac
Fix for C343-72, levitation on flying steed

* C343-72:   You get confusing messages when you stop levitating while on a
             flying steed.
             Author:  Edoardo Spadolini
             Source:  http://sourceforge.net/apps/trac/unnethack/changeset/958
Fix for C343-171, silver damage message to hero

* C343-171:  Silver weapon damage message is sometimes missing when hero is
             polymorphed.
             Author:  Patric Mueller
             Source:  http://sourceforge.net/apps/trac/unnethack/changeset/910
Fix for C343-174, drum of earthquake message

* C343-174:  Drum of earthquake gives inappropriate message if hero
             or monster is in a pit.
             Author:  Patric Mueller
             Source:  http://sourceforge.net/apps/trac/unnethack/changeset/948