#4 Add check for unique page names

[tavery]

Confluence requires unique page names in a space. If page names are not unique, the latest page overrides the previous page of the same name without providing an error. It would be great if there was a way to check that page names were unique.

[Lisa Dyer]

Assigning for further scoping. This might be appropriate in conjunction with the recent request to delete wiki pages when topics are removed from a DITA map.

Page title validation is not currently implemented because of the adverse affect on processing times during import due to the back-and-forth communication between dita2confluence and the target wiki. If implemented, it should be a config option with the default set to 'false'.