These textures (which come with normal maps, specular maps, and displacement maps), were primarily designed as an exercise with the Photoshop Clone Stamp tool. I grabbed these off of cgtextures and made them seamless, and created the maps with CrazyBump. If the developers think they're good enough, they can be included in the game (although my hopes are not high that they will be :D).
Have fun with them! If you like 'em enough, I will consider making more.