TodoView: Make behavior consistent with other views

Use double click on double click platforms.

Change-Id: I4ad6436dd56f370961db6a4bb8fcf788bd0cd579
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
CodecSelector: Use Utils::TreeView

No functionality change.

Change-Id: I09c3cd4afd84c75125ed184d8e96be9f537b62e0
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
GenericProposalWidget: Make Enter accept the selection too

To make it consistent with all other itemviews

Change-Id: I82f81c559106ba54d9f7ef32f0f4dfdb4b9f22c1
Reviewed-by: Eike Ziller <eike.ziller@digia.com>