Make an easy tool to fake an event, for debugging/testing clients

[hmpf]

The tool needs to be able to

1. create a new event (see if it turns up in the correct location)
2. close an existing event (admstate closed)
3. remove an existing (closed) event on the server (to see if it disappears in clients)

Changing admstate can be tested via existing clients so we do not need support for that.

Workaround: in-depth docs for how to do this via telnet though point 3 is probably not possible via telnet.

We decided to make this into a new API command and I think it is actually best to split it into three parts:

• Implement an API command that creates fake events #268
• Implement an API command that sets the state of existing events by the given id #269
• Implement an API command that deletes an event by the given id #270

[runborg]

as for point 2) the SETSTATE api command are able to set the state of an event, if you choose the state CLOSED it will be closed, if this command is usable use that instead reimplement it in #272