Rename 404 page and add a 500 page.
Call error method on exception
Add error page + email on error support to flight
Wrap pantheon on "layout" not on start (so errors are pantheonised even when flight fails & json feeds arn't)
Add auto suggest back to 404.
Don't suggest when we have no matches
Catch errors more liberally + formatting tweaks
Don't waste time generating programme map for 500 error pages (only 404)
Merge pull request #119 from unikent/feature/500-errors

Handle 500 errors nicely