Reduce debug output and use cout/cerr instead.

We have a message handler and would show the user our own debug
output otherwise, which is not desired.
Properly remote the selectionModelInspector.

This is done by pushing all QObject/QAbstractItemModel and
QItemSelectionModel logic to the server side and publishing a
QIdentityProxyModel which gets the selected source model as
source set. This then magically works on the remote client.

In pre-Qt4.7 this uses QSortFilterProxyModel as a fallback
instead of QIdentityProxyModel. It works just like it, just
slower.