Richard van der Hoff d5352cbba8 Handle url_previews with no content-type
avoid failing with an exception if the remote server doesn't give us a
Content-Type header.

Also, clean up the exception handling a bit.
2018-02-02 00:53:46 +00:00
..
2018-01-24 11:07:47 +01:00
2017-07-17 12:03:49 +01:00