Add an audio feedback mechanism
to play confirmation or rejection sound on specific actions that are not visually detectable.
here for "Duplicate" (mainly for the HMD use case where the new entity is generated at the exact same position)
Simpler solution without any hazardous uniqueness check.
Cloned entities will systematically get the suffix " (2)", unless their name has already a suffix.
In that case, we simply increment the suffix.
This enhancement adds an incremental suffix to the name
of the cloned entities resulting from "Duplicate" and "Paste".
The goal is to help to figure which entities is the coned one.
This addresses issue #575
