Add scrapers for Merton and Conwy (PlanningExplorer)

Add Blackburn and Greenwich (acolnet sites - patch from Peter Collingbourne.
Fixes to Ocella parser (also from Peter). Adds Bridgend, Castle Point, Great Yarmouth, Havering).
Fix typo and escaping in getinvolved (patch from David Sheldon).

This site is absolutely rubbish: 

1) It's impossible to link to the info page - needs a cookie. I've put a link to the search page for the moment.
2) Many applications have no description. I've put the text "Description Missing" when this happens.

we don't have postcodes.

Encode all output as UTF-8.