#10 Support texture switching

[Egal]

texture switching enables one model to look very different just by using a different texture. For example the same wall model could have textures for different types of brick or stone. This is probably not directly supported in .XSI so joXSI would have to be able to be given a regular expression that would match an image name and then choose a particular variation of the texture.

The UV mapping of the texture is contained in the .XSI model so the texture mapping would have to be the same.

[Steven West]

I'm working on this right now. In order to make this a bit simpler, modelers are going to have to change how they create XSI models. We need one triangleList per model, or some way to identify triangleLists by name.