Added open_uri_redirections to allow HTTP/HTTPS transfers

By default open-uri doesn't allow HTTP->HTTPS or HTTPS->HTTP redirects and this is causing the error reports in theodi/csvlint#53.

Added the open_uri_redirections gem which patches open-uri and we now allow both types of redirection.

@floppy can you think of any issues with this? (I can't as its all open data, but wanted a second opinion).