Merge Cpu0 backend example code into one copy

Sean,

I find a way to merge Cpu0 backend example code into one copy.
Now, the example code can be configured to build a specific chapter example code, or
generate chapters example code by run the program I written.
I find it’s much easy to maintain than the patch I did before.
I am keeping study llvm backend and writing, and I think this solution can apply in my future
work for those document/program which fit to explain them step by step.

Procedure as the following link,
http://jonathan2251.github.io/lbd/install.html#cpu0-document

Best regards

cschen

That is an interesting approach to keeping multiple stages at once.