Use new 1.7 block names in ID lists, since IDs aren't consistent and shouldn't be used here

Existing IDs in lists will work due to the way Block.getBlockFromName() works. I also added a warning message for numeric IDs. Since I couldn't be bothered to set up a proper dev environment right now, I haven't actually checked that this code compiles and works yet, but it should. If it doesn't, tell me and I'll fix it. I'll work on getting it set up so I can actually compile.