Temporarily simplifying chords
Song refactoring; moving printing and playing to Song instead of Driver
Added ChordPairs for an extra layer in the Markov chain
Moved management of unique Chords and ChordPairs to XMLReader
Unit tests for XMLReader Chord and ChordPairs
Unit test for adding a next chord
ChordPair unit tests
Test updates
No longer creating a new random generator on every chord
Pulling first I chord read in instead of a random chord as the seed for new songs
Fixed whitespace artifacts
Usage message added