Fixed issue with LOD and scaled models.

The general LOD strategies doesn't take scale into account. However,
since we use scaled entities quite a lot we need to handle this.
This change introduces a new LodStrategy which acts just as
Ogre::PixelCountLodStrategy but also takes scale into account.
It fixes the issue with some models using too low LOD level meshes.
Make calculation simpler.
Use max scale instead of min.

Since it's worse if a low LOD mesh is shown when it shouldn't, than the
reverse.
Update goal definition.
Improve rounding.
Added command for creating entity in inventory.

Instead of always creating it in the world.
Allow entities to be created in other entities.

The syntax is "/make entity_type parent_id".
Use std::shared_ptr instead of boost.
Use Ogre 1.9

 - OverlaySystem is now a component, add to build and initialize it in OgreSetup
 - Scene Managers can retrieve the OverlaySystem from OgreSetup and
   register it with themselves to show overlays.
 - Add some implemented methods due to Ogre interface changes.
 - Purge includes of OgreProgressiveMesh since it was removed.
 - TODO: use QueuedProgressiveMeshGenerator from Ogre. Current state
   throws some cast exceptions in the background.
Fix Ogre macro usage for Ogre 1.9

Now it requires ';' after the macro.
Use Ogre's built-in Lod generator.
Fix rebase.
Fix LodDefinition Lua bindings
Add include guards
Disable the use of EmberPagingSceneManager.

 - Remove EmberPagingSceneManager from the build
 - Create dummy implementations for the needed scene manager related classes.
 - Use Ogre default scene manager or OctreeSceneManager if loaded.
 - Comment out RaySceneQueries which depend on World Geometry being
   supported by the scene manager in AvatarTerrainCursor and
   ThirdPersonCameraMount
Rename ISceneManagerAdapter

 - ISceneManagerAdapter is responsible for managing terrain related
   data, therefore rename it to ITerrainAdapter.
Move main menu scene manager instantiation

 - Remove instantiation of scene manager for the main menu from
   OgreSetup.
 - Directly create it in EmberOgre instead.
 - Rename scene manager and camera objects in EmberOgre.

Fix formatting in Scene.cpp
Change terrain intersection testing.

- Introduce rayIntersects to ITerrainAdapter to let the terrain
  implementation decide how to check for ray collisions.
- Use rayIntersects instead of RaySceneQueries in AvatarTerrainCursor,
  MainCamera and ThirdPersonCameraMount.
- In MainCamera, a result for the RaySceneQuery is created manually if
  the ray intersects with the terrain so the listeners do not have to be
  changed.
Use ST_EXTERIOR_REAL_FAR to create scene manager
Pass ray by reference in ITerrainAdapter