Fix qtAttributeView response to advance level changes
This fixes bug where qtAttributeView, doesn't respond to changes in the general/advance level combo box. The underlying problem is that the current code calls qtAttributeView::onListBoxSelectionChanged()
which checks the current selected row with a cached value. The fix is to clear the cache variable before making that call.
To make it easy to see the bug, this MR also adds a small file attributeViewExample.sbt
to the lfs data.
Edited by John Tourtellott