Backport changes from trunk.

Hi Bill, this PR includes all the changes made previously in trunk for a 2.02b release, namely:

- The *Play Black* bug is fixed
- The new *Copy Game to Clipboard (PGN)* feature
- A fix to ensure the `Set Max CPU Cores` option is set correctly for StockFish
- A typo in `src\CtrlBox2.cpp` that prevented compilation has been fixed