Refactoring raptor.hs

I made the following changes:

1. Refactor to remove unnecessary let binding
2. Make the assumption that all of the IDs are in ascii, therefore using lazy ByteString to get better performance when processing data files.
3. Turn on ghc warning options, and fix several warnings during compilation.
4. Use cabal 1.16 to prevent mysterious bugs in the previous version if you are using cabal test in the future.
5. Write a simple bash script to run simple test cases.