Only embed https resources

[kannes]

http://www.cogeo.org/ redirects to https://www.cogeo.org/ which is a good thing. Unfortunately some external images are embedded via http. From those, the only the www.cbers.inpe.br one is not available via https. This makes browsers display warnings.

The site should not load any insecure external resources.

If you decide to work on this, please also see which of all the external links can be changed to https too. :)