Python Penultimate

Capabilities are almost feature complete. The program now successfully
takes a MIDI file and produces (what appear to be) working arrangements,
though more testing is required. As ever, caveats apply:

Unimplemented features remain:
- Auto-generated anchors.
- Handshapes (also automatic).
- Support for track metadata, particularly a song name, which remains
unsupported (absurdly).
- Previously-described MIDI Reader shortcomings.

Issues:
- A critical issue emerges through the particulars of Python's
referencing and copying. Appropriately copying the note and chord lists
between difficulties takes several seconds per difficulty, which is
unacceptable. Several alternatives must be tested.
- Redundancy across difficulties. The RSXML format typically reduces
file size by only including updated phrases or sections (not sure which
at present). As it stands, the Converter produces files of several
megabytes which, while not fatal, is certainly inconvenient.
- Generally, the entire experience is just a bit inferior to what EOF
offers. Should probably work on that.