Added support for authenticating proxies

git-svn-id: https://get-iplayer-automator.googlecode.com/svn/trunk@576 98b4c264-8670-11de-a133-9d545b4d7674
Convert dates in filenames to YYYY-MM-DD format

git-svn-id: https://get-iplayer-automator.googlecode.com/svn/trunk@577 98b4c264-8670-11de-a133-9d545b4d7674