(broken) saving container code creation using API
go client dropped. Implemented using docker binary.
more go-get-able
re-factored code. Container as checkpoint structure.

This doesn't work because the container will depend on the
image it was created from and thus all the new containers we
create will pile up on top of previous image. As a result, we
won't be able to remove the old images (because the last committed
one will depend in the previous last committed one, and so on).

The solution is to use always the same image as checkpoint, instead
of the container. The containers would be discarded after every
run whereas the image would be updated.