The event parsing code for webhook events incorrectly assumed there would

be spaces when there weren't. The parsing code has been updated to fix

this issue. Also, it will no return an empty list instead of a list

containing an empty string when no events are specified.
Additionally, the WebHookTarget model has been updated to allow for no

events to be specified.
Unit tests have been added to cover the new behaviour and ensure it does

not regress.

Ran unit tests.