Add .gitattributes (#843)
Add .gitattributes (#843)

This will allow smaller download size in production.

https://www.reddit.com/r/PHP/comments/2jzp6k/i_dont_need_your_tests_in_my_production
namepros/PHPMailer,ravisorg/PHPMailer,JesusTheHun/PHPMailer,pingyen/PHPMailer,Synchro/PHPMailer,Dubz/PHPMailer,iFixit/PHPMailer,jimjag/PHPMailer,nawawi/PHPMailer,PHPMailer/PHPMailer,martinvd/PHPMailer,PHPMailer/PHPMailer,Synchro/PHPMailer,namepros/PHPMailer,pingyen/PHPMailer,Dubz/PHPMailer,martinvd/PHPMailer,JesusTheHun/PHPMailer,ravisorg/PHPMailer,iFixit/PHPMailer,nawawi/PHPMailer,jimjag/PHPMailer