Modify the sendgrid API to handle Version 3 of the API. MJ-719 MJ-732
Remove commented test code and update code documentation. MJ-719 MJ-732
Fix doc. typos. MJ-719 MJ-732
Merge pull request #487 from DirectEmployers/sendgrid-v3-api

Modify the sendgrid API to handle Version 3 of the API.