Note skin, plumber build, source refactor, fixes

- Notes toggle using scribe commands
- New commands to collapse a single note and collapse all notes
- Separation of code into multiple sources
- Various fixes
- Implemented new styles for notes as a "skin" (src/skin/gu-noting.less):

![note-screenshot-2014-09-26](https://cloud.githubusercontent.com/assets/2298529/4418856/247466ee-4564-11e4-9208-e5d39986010d.png)

I think it makes the code a bit more readable in the places it's used, instead of having to do `function (focus) { return ! focusOnMarker(focus); }`.