buildpacks: Add support for installing dependencies during Docker image build time

References GH-44
buildpacks/php: Download heroku buildpack during Docker image compilation

References GH-44
buildpacks/python: Make it work again

Enough to close GH-44
docs: Initial introduction and getting started
Moar docs
A bit more docs
Update introduction.md
Update getting-started.md
Update project status
More work on docs
Add link to docker issues / PRs related to user namespaces
docs: Note that Im testing it on Docker 1.0.1+
docs: A couple tweaks to the home page
Update README
docs: Mention `rake db:create db:migrate` on discourse example so that I dont forget it when recording the video
Puma default port is 9292
docs: `--standalone` is not a real flag
docs: Sidekiq changed `rake spec` to `rake test`
docs: Getting close to enough docs for v0.0.1