EVENT_WAITFOR will hang in such a way you can't @Q

[tanabi]

EVENT_WAITFOR completely kills any attempt at input -- you can't @ Q out of it. Thusly, it should probably be something that either forces the program into BACKGROUND or raises an error that EVENT_WAITFOR only works for BACKGROUND processes. I think I'd prefer the error message because it will prevent WTF? programming mistakes. Make sure the man page is also updated.

Is there a reason to allow EVENT_WAITFOR to hang the foreground? It looks like MCP-GUI may be a reason, so before doing this change we should probably check how MCP-GUI MUFs are written to see if they seem to rely on a foregrounded EVENT_WAITFOR ... if they don't, then let's do this change. Figuring out this part is part of the ticket. (sorry)