Adding support for events on plain old objects
Removed duplication of plain objects to facilitate events on said objects

Duplication causes the event module to issue a new zid for every copy, rendering events on plain objects inoperable.
Fixed off() for plain objects.
Added tests for events on plain objects
Added test to verify that events trigger the appropriate listeners
Merge pull request #779 from andyjansson/master

Added support for events on plain objects