Editors: Remove useless parent widget argument from create/duplicate

It was never called with a sensible value anyhow, and only complicates things.

Change-Id: I005848700b6c00114d91495670d4a0e15a2d2e64
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
Fix splitting generic project file editor

Change-Id: If8e1e78d1895584bb03eb394f072d8c782a171b6
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
Editors: Remove some unused factory variables

Change-Id: I6df843561c4d502b3d7c1844d65a59ad2855f0c0
Reviewed-by: Daniel Teske <daniel.teske@digia.com>