Creates a folder.
Name of the directory to create, which is assumed to be in %A_WorkingDir% if an absolute path isn't specified.
[v1.1.04+]: This command is able to throw an exception on failure. For more information, see Runtime Errors.
ErrorLevel is set to 1 if there was a problem or 0 otherwise.
A_LastError is set to the result of the operating system's GetLastError() function.