Fixes #1209: Tarhiel never falls

There are a few pitfalls with this code:
 - Gravity is only considered when applying queued movement. Therefore, make sure to queue some movement every frame. (Could be refactored in the future?)
 - The character controller never detects being in free fall (!World::isOnGround) unless movement has been applied.

apps/openmw/mwmechanics/character.cpp

@@ -1245,12 +1245,8 @@ void CharacterController::update(float duration)
             else //avoid z-rotating for knockdown
                 world->rotateObject(mPtr, rot.x, rot.y, 0.0f, true);
 
-            // always control actual movement by animation unless this:
-            // FIXME: actor falling/landing should be controlled by physics engine
-            if(mMovementAnimVelocity == 0.0f && (vec.length() > 0.0f || mJumpState != JumpState_None))
-            {
+            if (mMovementAnimVelocity == 0)
                 world->queueMovement(mPtr, vec);
-            }
         }
 
         movement = vec;
@@ -1290,7 +1286,7 @@ void CharacterController::update(float duration)
         }
 
         // Update movement
-        if(moved.squaredLength() > 1.0f)
+        if(mMovementAnimVelocity > 0)
             world->queueMovement(mPtr, moved);
     }
     mSkipAnim = false;