Core/Units:

- Implement UNIT_FIELD_HOVERHEIGHT (requires DB data). This field, sent in update object packet, will determine the height at which a creature hovers if it has movementflag_hover applied. Note that hovering will now update the server-sided z-coordinate by the value of this field, and that all subsequent positional updates to the client will need to send z coordinate MINUS the hover height offset, or the hoverheight will be visually doubled client side.
- Correct our usage of movementflag_flying, movementflag_can_fly, movementflag_hover and movementflag_disable_gravity (previously levitate), and how they relate to InhabitType in the database. This fixes "flying creatures on steroids" bug (wings flapping too fast), and potentially a lot of visual issues in AI scripts. Note that a lot of scripts still set wrong movementflags, these need to be fixed on a case by case basis.
- Send correct packets for SPELL_AURA_FEATHER_FALL, SPELL_AURA_WATER_WALK and SPELL_AURA_HOVER apply/unapply.
- Send correct packet contents for movement update in Unit::SetSpeed.
- Misc. cleanup in affected scripts.

src/server/scripts/EasternKingdoms/undercity.cpp

@@ -114,7 +114,7 @@ public:
                     summoned->CastSpell(target, SPELL_RIBBON_OF_SOULS, false);
                 }
 
-                summoned->SetLevitate(true);
+                summoned->SetDisableGravity(true);
                 targetGUID = summoned->GetGUID();
             }
         }
@@ -184,7 +184,7 @@ public:
             {
                 if (EventMove_Timer <= diff)
                 {
-                    me->SetLevitate(true);
+                    me->SetDisableGravity(true);
                     me->MonsterMoveWithSpeed(me->GetPositionX(), me->GetPositionY(), HIGHBORNE_LOC_Y_NEW, me->GetDistance(me->GetPositionX(), me->GetPositionY(), HIGHBORNE_LOC_Y_NEW) / (5000 * 0.001f));
                     me->SetPosition(me->GetPositionX(), me->GetPositionY(), HIGHBORNE_LOC_Y_NEW, me->GetOrientation());
                     EventMove = false;