Discworld 1 Demo support added to SVN

Whilst it's nowhere near as spectacular as adding support for Discworld 2, the latest SVN code now supports the original Discworld 1 Demo.

This demo is somewhat interesting in that it was built at an early stage during the development of the first game. As such, it used a more primitive version of the source code used in the final game. Luckily, it didn't prove too hard to cross-reference a disassembly of the demo executable and identify commonalities between it and the DW1 v1 source code, and from there work out what had changed.

The demo version I used during development was downloaded from Adventure-Treff.

There were actually two demos released for DW1 - this first one contained only the two 'rooms'.. the Fishmonger's and Alley, and the single objective of getting the belt buckle. Please note that this version does not have any sound.

The second demo released apparently contained most of Act I, and featured full voices and SFX. If anyone knows where a copy of that version can be located, I'd be interested in making sure that that version also works with our Tinsel engine.