Update providers.json

Added MX records for Yahoo mail.
Merge pull request #666 from rlaferla/master

Update providers.json
Fixed #671: workaround bad message encoding
Gitignore file has been improved.
Merge pull request #672 from maximkhatskevich/master

Gitignore file has been improved.
deletion of ending characters made easier
Fixed type conversion
Fixed build of mailcore2 for iOS 7.1
Made very short display string even shorter
Merge branch 'master' into relateiq_profiles