`BOOL` becomes `bool` and related (1)

`BOOL` becomes `bool` and related (1)

* Retains `BOOL` where necessary for MFC or Win API interfaces
* Retains `BOOL` in `*.c` files (GNU diffutils, and others) as `bool` is unavailable
* Mostly retains `BOOL` in CrystalEdit and BCMenu related files
* Retains `BOOL` in Poco and Boost source files.
* Retains `BOOL` when used with values other than simply `TRUE` and `FALSE`, such as values of
`-1`, or with additional flag bits.  These should be modernized with some future commits.
* Also `TRUE` becomes `true` and `FALSE` becomes `false` where appropriate.