Change info buttons to be positioned consistently

- Always position them after the h1
- First pass at progressively enhanced CSS -> JS
    Info box appears on hover if JS is disabled
                        click          enabled
Add CSS to style border-top on all modules
Move module_actions to a preprocessor
Move stacked graph linelabel down by 20px

So as to not overlap the more info link.
Revert to previous module_actions.js for more info

Move tests from spec/javascripts/common into spec/javascripts/spec/common
so that they actually get run.

Use a different class for figuring out whether JS is enabled. It's faster.
Merge pull request #243 from alphagov/58617804-info-buttons

Implement improved info buttons [#58617804]