Updated providers.json 

Updated for additional GMAIL MX records.
Update providers.json

Removed duplicate entries.
Merge pull request #649 from marcopifferi/master

Remove unused variable to avoid compilation warning.
Use SSLv3 to workaround curl issue
Updated to libetpan 1e5bb22b0b560175faed91430c6ee7de0c818f88
Merge pull request #648 from rlaferla/master

Updated providers.json
Merge pull request #2 from MailCore/master

merge lastest MailCore