Add command line export

[mtkennerly]

• Documented existing CLI functionality and added MIDI/WAV export via CLI.
• Because of how the WAV export is coupled to the GUI, I ended up using an event callback. For MIDI, I thought it was more straightforward to just make a new method in midicontrol.as rather than trying to extricate onsavemidi() from savemidi().
• Added BoscaCeoil.swf to the ignore file since the build instructions and application.xml point to it being at the root of the repository.