Add Docker support

This addresses the first set of tasks in Issue #97.

The branch with the ``Dockerfile`` in it has been used to create a Docker image and pushed up to Docker Hub. As such, the instructions provided in the ``README.md`` for this branch work even without this branch getting merged.

However, once this is merged and the next release of LFE is tagged, we will be able to submit PRs to the Official Docker repos and get an official Docker image for LFE published.