adding codebreaker (untested), extend_array

CodeBreaker is coming along. I'm in the weeds trying to get it to
evaluate key_pegs correctly. I've decided that it would be nice to have
Arrays simply swap the values of two given indexes, so I've extended the
class to include that: array.swap_values(first_index,second_index).

I don't know how to include the extension in my project yet though.

Another extension I'm considering is a shuffle_select to Array. It would
be something like array.shuffle_select(array_of_indexes). That would be
nice.