Use download method which works with proxies which require authentication

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Fixed issue #2067: Normalize email with capital letters when calculating gravatar hash

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
This is git, not subversion

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>