Blockquote margins
Add small script to setup label in lesson repo

The script make easy to create the labels and keep it compatible
across repositories.
Improve script to setup labels

Address @gvwilson comments:

- add an example
- variables in the shell are UPPER_CASED
- Check that repository exists using a HEAD
Avoid JSON outup from setup-labels

As requested by @gvwilson, don't print the JSON response from
GitHub.

Others changes:

- Use arrays to store the label and its color
- Print message if fail
Improve callout box

and "learning objectives" box.
fill in missing '$ ' in prompt
Merge pull request #18 from r-gaia-cs/add-script-for-label

Add small script to setup label in lesson repo
Merging CSS
Merge pull request #29 from r-gaia-cs/callout-box

Improve callout box and "learning objectives" box
Merge pull request #47 from aaren/fix-prompt-sign

fill in missing '$ ' in prompt