H2 slugs changed to make anchor text linking logical

slugs are now:
- the name of the numbered section that H2 appears in, followed by
- all the words that appear in the title (ignoring all punctuation)

Example:
news-stories-titles
policy-pages-titles
publications-titles
and
policy-pages-who-were-consulting-or-who-weve-consulted-optional-and-depending-on-time
Merge pull request #55 from ElenaFdR/patch-1

H2 slugs changed to make anchor text linking logical