Most traps now require touching the floor to trigger

It was silly how some clearly mechanical traps didn't consider
flight or levitation when to trigger.  Do those checks in dotrap/mintrap
making hero and monster trap triggering match more closely.

doc/fixes3-7-0.txt

@@ -818,6 +818,7 @@ discovering an object on first turn with persistent inventory enabled might
 	not update inventory info for that item (autopickup a blank scroll
 	or spellbook and read it as first action; it becomes discovered but
 	will still be shown as if undiscovered until next inventory update)
+most traps now require touching the floor to trigger
 
 
 Fixes to 3.7.0-x Problems that Were Exposed Via git Repository