Include icons in the Windows installer

Also fix the dependency / ordering issue with running makensis

Fixes #252

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
This moves the removal code to the model.

It's very important when programming via Model/View, in gtk or qt,
to not mess with the model data outside of the model. We were
deleting stuff that the model controlled outside of the model, so
it thought that there was still data there. This fixes the deletion
part, but there are also lots of other parts that I'll tackle in
the next commits.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>