Docker based build + new Docker port + VBoxSF included + non regression tests

Hi !

This PR embed :
* A brand new build workflow "eating its own dog food" (we use a boot2docker vagrant box for running Docker). It's a lightweight and customizable build process (you can use the Docker trusted build of b2d, or specify a change set of the original boot2docker repo. You can also add your own piece of cake).
* Using a recent version of b2d and docker (1.1.0).
* We can use rsync for shared folder, but Virtualbox and NFS also works !
* Nat is bound to the new official Docker port, and collision are auto-detected
* Some non regression tests (based on bats) are included. They can be tuned and growth.


Some advices ?