Show issues in spec

[marcoscaceres]

It would be nice to show (GitHub) issues in the spec, by allowing uses to a drop in the URL of the issue tracker. Then, the issues could be dynamically added to Editor's draft with the option to:

1. show the issues in its own section
2. try to match issues to sections (e.g., using something like "[id] some issues", which attaches the issue to some element in the spec).
3. allow specs to be published with issues or with some boilerplate linking to issues.

See the following for a prototype:
http://picture.responsiveimages.org/#open-issues

[darobin]

This is a great feature (and likewise contributors and such) but it should be dynamic. ReSpec doesn't handle anything once a static version has been produced. This should really go into https://github.com/darobin/specstatic!