Multithreading, Time dilation and Repackaged

Okay, I've reorganised the source files into new packages, with 4 main
branches:
Logic - intended for the update loop alone
Render - intended for all rendering systems (OpenGL, DirectX etc.)
Uni - short for universal, intended for use by both systems
Debug - Just general debug tools, may be universal - may not

It's also multithreaded now. The draw thread runs as the main thread and
the update thread runs as an additional thread. The threads communicate
via triple buffers - in particular render objects are transmitted that
way.

Since the update speed is no longer linked to the draw speed, I've
implemented a sudo-variable timestep that provides a constant speed
regardless of the target update or draw speed. This has also allowed me
to add a secondary modifier that can either speed up or slow down time -
without making the motion choppy.