Add a test parsing a JSON

Parsing https://api.github.com/repos/discoverygarden/islandora_critical_edition/commits/382ef451cee512f798c624d51b5fd372670f2063 once raised an error: Found multiple JSON objects in the stream but no block or the on_parse_complete callback was assigned to handle them. (Yajl::ParseError) but not for the JSON downloaded afterwards