This is the beginnings of a library and test suite for reading lilypond
fragments.

lilypond.interp.parse will take a lilypond fragment and generate a series of
core.Points with attributes OFFSET_64, MIDI_PITCH and DURATION_64.

To ensure trailing rests don't get lost, some Points have an OFFSET_64 but
no MIDI_PITCH or DURATION_64. These don't correspond to any note but instead
mark the end of the block.

You can run tests with by running `lilypond_tests.py` under top-level `tests`
directory.
