ReCaptcha causes IE warning when using SSL (HTTPS)

When accessing a CiviCRM page via SSL (HTTPS) and it contains the ReCaptcha HTML snippet, the ReCaptcha HTML does not submit to an HTTPS URL and triggers an IE browser warning about "mixed-content": "This page contains both secure and nonsecure items. Do you want to display the non secure items"

Attached is a patch against CVS HEAD that detects if the page that the ReCAPTCHA HTML will be injected into is going to be served out via SSL (HTTPS). If it is SSL, then it tells the ReCAPTCHA package to use an HTTPS URL for the submit.