columns: 1. texture, 2. block id, 3. unused, 4. biome id, 5. priority
columns: 1. texture, 2. block id, 3. block texture, 4. unused, 5. priority
The "block texture" in the third column is an optional 8x8 texture encoded in base 64. If you're really ambitious, you can decode it with this bit of Java code: https://gist.github.com/4044166
Good luck. =p
Oh my God thank you so much! I can see why this took you so long, your dedication is amazing! Thanks for this awesome map and info I will start working on the texture pack this weekend!
And I must say, those are a lot of textures. I will probably just take the first texture for each block. I don't think it should take too long with Ctrl+F