JS to auto open linked-to sections

- On pageload open the section in the hash, if there is one
- Catch any links within a govspeak block and check if they are linking to somewhere else on this page. If they are, open that section. If they aren't then allow the event to propagate.
Fix link handling

- add missing var
- remove preventDefault because we actually want the default thing to happen
- fix variable name
Merge pull request #27 from alphagov/js-auto-open-section

JS to auto open linked-to sections