This will allow the core client to kill VirtualBox VM's launched indirectly by vboxwrapper. Vboxwrapper launches vboxsvc.exe which launches vboxheadless.exe. This should also take care of the core client being able to kill child processes of the regular wrapper as well. I don't know the full scope of this type of issue? Maybe the default ACLs for a process changed within the last couple of versions of Windows.
* Move the windows_format_error_string function to win_util.cpp, .h instead of it being scattered between util.h and str_util.cpp.
* Convert the Windows error string into UTF8 before allowing it to be used by the caller
* Remove windows_error_string from library