It should be possible to save and load a Bubbles composition

[colinbdclark]

User story:

An artist should be able to save their composition to a file on disk, and load it back into the program. Saving a project should capture all the essential state of the composition, including the current playback time of each video, the modulation values of each parameter, and the MIDI device that has been connected to.

This feature will require moving or relaying some further data (I think) into the "megamodel" of the bubbles.composition component.