Added support for gmail-based notifications, as well as changed README to reflect new feature.

> Users now specify which method they'd like to receive messages through, though they can only specify one. The password for sending email via Gmail may need to be an application specific password (depending on their security settings).
> Currently, an email is sent from the users account to themselves. With support for more generic email providers, it may be possible to send emails to whoever.

Changed the name of a variable

> There was a variable named "entrie", which has now been changed to "entry".