Added support for the content type application/json; charset=utf-8

One liner to add check if the content-type contains application/json instead of equals the string.  That way if the charset is included it still tries to decode the JSON data.  

Also, if you only do the -U option, it would exit with status UNKNOWN, updated it to exit with status OK.

Bumped the version from 1.00 to 1.01.

Thanks for sharing this, it was super useful and saved me a ton of time!
-James