Update documentation

[kevinschaul]

The Getting Started section in the wiki notes that "This documentation may not be up to date with bones releases."

Well, it isn't. I'd be happy to update if I could wrap my head around the project.

[springmeyer]

We are not actively developing bones - maybe you could share why you are using it?

[kevinschaul]

I'm looking into an application structure similar to Tilemill. Isn't that using bones?

[springmeyer]

TileMill 0.10.x does yes, but we are working on a new version of TileMill 2.x that does not: https://github.com/mapbox/tm2