The world loading process was improved

Entities are once again loaded by a Lua script. This doesn't work on 64
bit because of issues with JavaLua native DLL.

The textures for terrain and sky are now loaded from the database using
the world asset list. This means there is no longer a pause on the ui
thread whilst file io happens.
Autosave system and Physics callbacks

An autosave system has been added which saves the game on a set
interval. This happens on a separate thread so that there is no
noticeable pause in game. At the moment there is no callback when the
save is complete, this would be useful twofold, one, so that feedback
can be given to the player and two, so that no other save operation can
occur whilst another is taking place.