Return response code 500, when rendering error.

While the response code might not be that important, if a human sees the
rendered error page, it might make a big difference, if the request was
an AJAX request.
Merge pull request #7 from hannobraun/500-error

Return response code 500, when rendering error.
Added new constructor for router NewWithPrefix and corresponding test + gofmt
Merge pull request #10 from pengux/master

Added new constructor for router NewWithPrefix and corresponding test + gofmt
Add Godoc reference badge
Merge pull request #12 from fatih/patch-1

Add Godoc reference badge