update doc to newer go
hack/ROADMAP.md: a high-level roadmap. Make a pull request to suggest changes
hack/PRINCIPLES.md: a list of principles guiding Docker's design. The goal is to scale the decision-making in the project and remove @shykes as a bottleneck as much as possible
changed to 12.04 and add kernel
Merge pull request #827 from dotcloud/dev_environment_update

Update "Setting Up a Dev Environment" doc, with modern golang  PPA and stable lxc kernel
Merge branch 'master' of ssh://github.com/dotcloud/docker
docker-build contrib script is deprecated by the new 'build' command
Daniel Mizyrycki is maintainer of dockerbuilder, the official build environment for docker binary releases
Update README.md