Try and make README more comprehensive.

Mostly Copy/Paste from the issue upstream.

Docker-DCO-1.1-Signed-off-by: Paul Nasrat <pnasrat@gmail.com> (github: pnasrat)
Register all types in frame.go; write stub proto messages
Merge pull request #5 from pnasrat/improve-fuse-readme

Improve fuse readme
Implement FileSystem.Chmod

Fixes bradfitz/docker#1
Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)