Demote ComponentFactory to ComponentRegistry

Since components are constructed directly in Lua now, we don't
need a factory anymore. The ComponentRegistry only handles the
conversion between type id and type name now.
Change EntityFilter to provide components for added entities

No need to be secretive. If the entity is relevant for the
filter, it has all required components. Providing them directly
in the EntityFilter::addedEntities() collection makes some
systems easier.
Add OgreSceneNode systems and rename Mesh* to OgreEntity*

Keeping our component API close to Ogre's architecture makes it
a little harder on script authors, but greatly facilitates
management of scene nodes and movable objects in Ogre.
Added EntityFilter::clearChanges
Updated Ogre components and systems

This should be it for Revolutionary-Games/Thrive#15.
Merge pull request #19 from Nimbal/ogre

Reworked the Ogre components and systems