so many changes
refactor to operate on bytes
more refactoring
use optimized popcount algorithm

http://stackoverflow.com/questions/1639723/ruby-count-the-number-of-1s-in-a-binary-number
refactor string scoring algo
refactor decrypt to work with repeating cipher keys
remove commented code
refactor code from challenge 6
refactor find_decryption_in_file to be more general purpose
refactor some test stuff
add a console
readability cleanup
refactor and add unit tests for the utils methods