Rename/Merge Events plugin

The Rename/Merge Events plugin can be used to rename events. When multiple renaming rules are inputted, the renaming is executed in the given order where renamed events can again be further renamed by following renaming rules. For the moment the plugin renames a 'Task' (event name) or an 'Originator' (resource) using exact case sensitive search.
The Rename/Merge Events plugin can also be used to merge two events together (to form a single new event replacing the two old ones). When multiple merging rules are inputted, the merging is executed in the given order where merged events can again be further merged by following merging rules. For the moment the plugin uses an exact case sensitive search. The new event is created with
- a given name
- all the attributes of the second event if that event has status 'complete'
- all the attributes of the first event otherwise

