Use an event for receiving player names.
The clean-up can now be handled locally.
Rename struct receiver.
Otherwise, there can be conflicting definitions of member functions,
even if the struct itself is local.
Add sound subscription of events.
Replace sound effects with events in parse.cpp.
Use event for sound when things drop.
Inventory shall no longer select what sound to use.
Make a general purpose failure event.
Use it from Inventory.
Create events for changing game mode.
Use it to terminate the TSExec thread.
Update comments.