Don't clean eventbus in compare configuration

Change-Id: I6841366324d6092f6efba9769eb06be78c0e216d
Signed-off-by: Axel Richard <axel.richard@obeo.fr>
ResourcesAttachmentChanges must be filtered in groups

Fix regression from e28f6d6e172ad4440bba23927f4373a7ed4a47c7

Change-Id: Ibe3eb38a03dc0a35a82362c4976dfe2bc50cba7c
Signed-off-by: Axel Richard <axel.richard@obeo.fr>
Do not create all TreeItems of the structure viewer eagerly

We were previously creating all TreeItems eagerly (and multiple times
every time the comparison is displayed or updated). This implies a lot
of useless work which, even worse, is done on the UI thread. We now
lazily create them on demand instead.

Change-Id: I4f260f7ebf69ac812dfdd9dae09f232829de2694
Signed-off-by: Laurent Goubet <laurent.goubet@obeo.fr>