Set site_name and signature email variables for alerts

so we can include the name of the site non TT templated emails
Only return html from problem->body if we have context

this means we can use this in email templates and get the correct non
html text back even if AREA_LINKS_FROM_PROBLEM is true
Update all email templates with new text.

And FixMyStreet.com specific open questionnaire page.
Merge branch '700-auto-emails'
Latest pulled translations from Transifex.
Version 1.4.