Fixing crash after "New device Wizard": instead of crashing, just unload the current device if the engine loading fails, giving the user another chance to retry.
Fixing device loading adding a queue. This also avoids double loading a device.
Fixing device close: queue to close the engine only if we've found it.
Fixing "New device wizard" size, and more checks against already inserted values (don't hide "next" if we already selected things..)
Cleaning old commented code.