Splatting doesn't correctly use the tiling specified for each layer

The terrain layer specification allows us to set a "tile size", which is the size in meters of each texture before it repeats. It's defined in the moraf.terrain file http://git.worldforge.org/?p=ember.git;a=blob;f=src/components/ogre/modeldefinitions/moraf.terrain;h=d2cd4ef0dea2733a82f9984c8022452db9a059f3;hb=HEAD and then accessable through TerrainLayerDefinition::getTileSize.

However, for some reason the values specified here weren't then correctly sent on to the Cg shader. I didn't have time to investigate why and instead just set all layers in the Cg shader to use the same tile size. This lead to some of the layers, for example the area below the oaks, to be incorrectly scaled.
Now that we've updated the shaders we should make sure that they do properly use the correct tile size, and also investigate and fix it so that the Cg shaders also use it (as it's the fallback for DirectX).