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/game/AI/ScriptedAI/ScriptedFollowerAI.cpp

@@ -93,7 +93,7 @@ void FollowerAI::MoveInLineOfSight(Unit* who)
         if (HasFollowState(STATE_FOLLOW_INPROGRESS) && AssistPlayerInCombat(who))
             return;
 
-        if (!me->canFly() && me->GetDistanceZ(who) > CREATURE_Z_ATTACK_RANGE)
+        if (!me->CanFly() && me->GetDistanceZ(who) > CREATURE_Z_ATTACK_RANGE)
             return;
 
         if (me->IsHostileTo(who))