Containerized version of tmkit now available

Posting this here as a reference.

I've managed to create a Docker image which builds tmkit. The code as well as usage instructions can be found at the following URL:

https://github.com/theredcomputer/tmkit-docker

Please note that it runs Ubuntu 16.04 for the time being. According to Quicklisp's maintainer, Quicklisp's package list should be updated with the latest version of CLPython at the end of November. At that time, the version of the Docker image can (or will) be bumped up to 18.04.

For convenience, I've also created a prebuilt Docker image available from Docker Hub. It can be acquired by running the following command:

`$ docker pull theredcomputer/tmkit_docker`

Here's to hoping this is of some use to you.