adding a 'slow-send' functionality for Google Apps mailing list

I've updated the github repo Google-Apps-Script-mailing-list with a script file which does 'slow-send' for large mailing lists which can be sent over several days. 

Slow-send-one-by-one.gs

Features - 

• time-based trigger, programmatically created and removed
• sends emails to each recipient individually, ramping up from sending
  24 emails per day (once an hour)
  to 96 (once every 15 minutes)
  to 144 (once every 10 minutes)
  to 288 emails per day (once every 5 minutes). This could be increased further, too.
• uses GmailApp instead of MailApp, so we can have features like name (of sender), alias, reply-to, etc.