Added `customData` and `extendedData` to Events.

`ATLog` has DEBUG, INFO, and ERROR log levels currently.

This is the console output of an Event 422. I added the custom note about `customData` and `extendedData` (similar to the note about missing API key) but the server's error will be shown as well.

 > [error] Connection failed. Unprocessable Entity, The request was well-formed but was unable to be followed due to semantic errors.
 > [info] Status was: 422
 > [debug] Event was invalid; sent with malformed customData or extendedData.
 > [info] ATAPIRequest failed: Unprocessable Entity, The request was well-formed but was unable to be followed due to semantic errors.