print script content in CLI

[babsey]

With this PR user can review the script content loaded from git.
To print the script content user has to select a record by label

sample command:
smt script <label>

It displays the name of the script, the git version and the content

[coveralls]

Coverage decreased (-0.2%) to 72.622% when pulling f836377 on babsey:CLI_script_content into 9341bf6 on open-research:master.

[apdavison]

I like this feature, and have merged the PR, but I would like to generalize it to all record fields by having an smt view command - see #364
i.e. smt view --script --version <label> or smt view -sv <label> would be equivalent to smt script <label>