HorizontalProxyModel now inherits from QIdentityProxyModel which provides a more complete base implementation (maybe to much?)
for now it seems to do what we want, forward relevant signals which the abstract base didn't.
Issues: Properties table needs formatting and shows all rows as columns instead of values of a single row.
model is reset as this will clear all selections.
Unfortunatly the selection model does not trigger a selectionChanged when
the model is reset.
Close#16
For now the create is still single line. Either complex query is required
to get details for custom generator or we need to format after the fact.
Close#12
The old name followed the pattern used by Qt to automatically deduce what signal should
be connected to which slot. However as these are signals from a sub object it cannot find
them and I have made the connections manually. To prevent getting warnings at runtime
I changed the name.
