Improve explanation of changes

[Mellbourn]

This seems like an interesting product but it would be great if the readme explained more of how changes are handled. For example, if you change a file, is it then possible to commit that change?

[billziss-gh]

HUBFS use case scenario is to support browsing of repositories and allow local builds to be performed without cloning. So it is not possible (at least currently) to push changes back into the origin repo.

I will look into improving the documentation to make this more obvious.

[c-nv-s]

Any progress on this project? Possible performance tricks or improvements would be good