Properties of Custom Paint

Hi all,

We wanted to start kicking off more discussions on the mailing list. As a
starting point Shane & I sat down and wrote up what we think are the
desirable properties of custom paint.

See https://gist.github.com/bfgeek/758b54a1cab65dff9d69

Feel free to respond here, or directly on the gist.

Thanks,
Ian