An implementation of Douglas Hofstadter's copycat algorithm

This implementation is a copycat of Scott Boland's Java implementation, but re-written into Python. It's not a direct translation - but based on his code. I did not carry over the GUI, as this version can more usefully be run from command line, or imported for use by other Python scripts.

In cases where I could not grok the Java implementation easily I took ideas from the LISP implementation, or directly from Melanie Mitchell's "Analogy-Making as Perception"

I also tried to make the code more pythonic.