Made ViewHandler::getSerializationContext protected
Merge pull request #779 from abstrus/issue-778

ViewHandler::getSerializationContext must not be public
adjust upgrading guide
Change BodyListener to not throw exception for empty DELETE requests

When a DELETE is empty and don't have the Content-Type header set, do not
throw the UnsupportedMediaTypeHttpException.
Merge pull request #786 from eriksencosta/body-listener-empty-delete-requests

Change BodyListener to not throw exception for empty DELETE requests
Fixed code style