update sendgrid code to latest sendgrid

In February 2014, SMTP support was removed from official SendGrid libraries
https://github.com/sendgrid/sendgrid-php/commit/0e80bece760746a1ee9caa5db5a7d790f678dc14

This updates the library to send with web
Merge pull request #1 from nquinlan/master

modify sendgrid code