Improvements for Docker integrataion

[paaguti]

In addition to cleaning up stupid typos in Readme.md, I have moved the Dockerfile to

1. Run clj as a non privileged user
2. mount the cloned app.core instead of copying it inside the container

This allows some edits to reflect on a running themecreator container on-the-fly, making development easier

In addition, I have updated the helper scripts to reflect the changes in Dockerfile

[mswift42]

Thanks, great work.