Update hello_collision.adoc

Fixed list continuation errors under 3. setWalkDirection().
Turned tip and important texts into Admonitions.

src/docs/asciidoc/jme3/beginner/hello_collision.adoc

@@ -16,7 +16,7 @@ You use a `RigidBodyControl` for the static collidable scene, and a `CharacterCo
 You can use the solution shown here for first-person shooters, mazes, and similar games.
 
 
-image::jme3/beginner/beginner-scene.png[beginner-scene.png,with="360",height="281",align="center"]
+image::jme3/beginner/beginner-scene.png[beginner-scene.png,360,281,align="center"]
 
 
 
@@ -307,7 +307,10 @@ To use collision detection, you add a RigidBodyControl to the `sceneModel` Spati
 *  Add the control to the Spatial to give it physical properties. 
 *  As always, attach the sceneModel to the rootNode to make it visible.
 
-*Tip:* Remember to add a light source so you can see the scene.
+[TIP]
+====
+Remember to add a light source so you can see the scene.
+====
 
 
 === The Physics-Controlled Player
@@ -482,21 +485,26 @@ This is how the walking is triggered:
 .  Initialize the vector `walkDirection` to zero. This is where you want to store the calculated walk direction.
 ..  Add to `walkDirection` the recent motion vectors that you polled from the camera. This way it is posible for a character to move forward and to the left simultaneously, for example! 
 ..  This one last line does the “walking magic: 
++
 [source,java]
 ----
 player.setWalkDirection(walkDirection);
 ----
-
- Always use `setWalkDirection()` to make a physics-controlled object move continuously, and the physics engine handles collision detection for you.
++
+Always use `setWalkDirection()` to make a physics-controlled object move continuously, and the physics engine handles collision detection for you.
 
 ..  Make the first-person camera object follow along with the physics-controlled player:
++
 [source,java]
 ----
 cam.setLocation(player.getPhysicsLocation());
 ----
 
 
-*Important:* Again, do not use `setLocalTranslation()` to walk the player around. You will get it stuck by overlapping with another physical object. You can put the player in a start position with `setPhysicalLocation()` if you make sure to place it a bit above the floor and away from obstacles.
+[IMPORTANT]
+====
+Again, do not use `setLocalTranslation()` to walk the player around. You will get it stuck by overlapping with another physical object. You can put the player in a start position with `setPhysicalLocation()` if you make sure to place it a bit above the floor and away from obstacles.
+====
 
 
 == Conclusion