Add in test version warning to initial map page

Warning to say that reports will not be sent to the council to avoid
confusion in advance of beta testing

Fixes #94
Geolocation error was never shown if accuracy check failed

If we got a geolocation fix but not one that met the accuracy check then
the locating screen was being hidden but the error message was never
being displayed.
Improve geolocation failed error message

Fixes #96
Correctly close location error message tag
Reduce location error message margins for better display

Too much veritical space in error message before