Added version and URL header

fix: false positives caused by auto-mode-alist pattern

The old pattern would match the following filenames:

- *Dockerfile
- *Dockerfile.*

This is because the pattern does not start with a slash indicating the
beginning of the basename. Personally this led to a few false positives,
like for example "siren-dockerfile.el" that sets up and configures
dockerfile-mode in my Emacs configuration.

This change restricts the patterns to:

- Dockerfile
- Dockerfile.*
- *.dockerfile

I believe this is still wide enough to capture all common naming
conventions for Dockerfiles.

Remove keybinding to #'dockerfile-test-function

Merge pull request spotify#19 from giuseppe/giuseppe/color-label

dockerfile-mode.el: add LABEL to the list of known keywords

Merge pull request spotify#10 from j0ni/accommodate-ethan-wspace

Correctly set require-final-newline

Added copy and onbuild commands