Firefly-v3.0.0

massive changes, biggest ones:

1. replacement of JSONs with .ffly binary format (much smaller and much faster to read!)
2. ability to optionally format binary data into .fftree, indexed by an octree.json file allowing the app to progressively render only what is on screen
3. super slick new UI (all credit to @ageller !!)
4. longstanding bug fixes
5. the ability to scale radius by any field
6. official support for the column density rendering mode
7. updated the default dataset to reflect the all the new features! (it's big though, 73 Mb so don't use mobile data...)

And probably more.