#218 TONE is not HALT-able -- causes data loss

[David Costanzo]

If you accidentally run a TONE for a very long time,
there is no way to HALT it without killing FMSLogo. As
a result, this should be considered a data loss bug.

The problem is that FMSLogo generates the tone using
Beep(). As mentioned on the MSDN:

The function is synchronous; it performs an
alertable wait and does not return control to
its caller until the sound finishes.

As such, I don't know how much can be done about this bug.

How Reproducible:
Every Time

Steps to Reproduce:
1) TONE 40 30000
2) Click the "Halt" button

What Happens:
FMSLogo plays a tone for 30 seconds. During this time,
FMSLogo is completely unresponsive.

Expected Result:
FMSLogo starts to play a tone, but stops when you press
"Halt".

[David Costanzo]

I have fixed this in [r6043]. Instead of calling Beep, the code now creates a waveform in memory and using wxSound to start and stop it. While the sound is playing, the code checks the message queue for new events (like a Halt). This fix will be available in FMSLogo 8.4.0.

This might have strange side-effects, like continuing the duration if a TONE is interrupted by a long-running instruction.