Improvements to robustness of CThreadPool. Rationalised CThreadPool a bit, so that only the main thread is used for thread death notifications. This means that the death of parent threads no longer causes a panic when the child threads is shut down.

X one
X twoX threeX four
X five
X six
X seven…X eight
X nine
X ten

Before 111
Before 222
Before 333…Match
After 111
After 222
After 333
And so on and so on
And so on and so on