improved layout modifications
Improved demo dimensions and options layout
Attempt to provide default height when not provided
Fixed lingering bug in source legends
Better inversion scale
Start using dagre-d3.
Added dependencies to makefile
Browser key-codes
Movement. Better highlighting.
Have to update d3's state as well as ours
Refactored into modules.
Added fiting logic.

And this time around it is actually sensible, and not totally baroque.
Use liveify to build, Centre on zoom.
Added smooth zoom
Adding ontology dag demo
Now with working ontology chart that does sensible filtering
Much nicer high level term controls
Better fit recurrance. Also, added low-level terms box
Listening to the right hiding event
Now with co-herent high/low level term switching.