Return object in OwnedArray add routines
Large tidying up of Beast

- Move key classes into beast_core
- Tidy up various macros and files
- Disable leaking FifoFreeStoreWithTLS
Tidy up and activate the MSVC Debug Heap
Use LeakChecked throughout Beast
Rename SharedSingleton and move files around
Fix File::nonexistent false leak using SharedSingleton
Remove beast::Singleton
Tidy up project file
Default MSVC CRT Debug heap leak checks to ON
Tidy up LeakChecked and configuration macro
Tidy up List documentation
Remove ConcurrentObject and rename to SharedData
FreeBSD tuning.
Linux implementation of isRunningUnderDebugger using ptrace() doesn't work on FreeBSD.
(I doubt it'll work on Linux, too, but I'm not sure)
Update some beast container code
constness fix in OwnedArray
Fix for atomic aliasing in Clang or GCC builds
Add neverDestroyed lifetime for SharedSingleton
Fix beast macro calls
Various beast cleanups