Fix a crash after adding favourites to browser when the item is not yet populated

The model was getting broken due to list of children being overwritten and
it was sometimes crashing in the proxy model implementation.
german translation update
Drop execute flag from .cpp file
attribute dialog: keep clone feature until destruction (fixes crash from action
menu)
Fix missing show/hide selected layers icons
Avoid unneeded geometry cloning in QgsGeometry::nodeGeometries

Affects splitGeometry and reshapeGeometry public functions
Revert "attribute dialog: keep clone feature until destruction (fixes crash from action"

This reverts commit f9fcee980ec7fb721187080f853f86dfbf453918.
Use a copy of the feature for the action menu in the attribute dialog
Merge pull request #1668 from m-kuhn/action-menu-crash

Alternative approach to f9fcee9