Win32: non-ASCII directory names support in ngx_create_dir(). This makes it possible to create directories under prefix with non-ASCII characters, as well as makes it possible to create directories with non-ASCII characters when using the dav module (ticket #1433). To ensure that the dav module operations are restricted similarly to other file operations (in particular, short names are not allowed), the ngx_win32_check_filename() function is used. It improved to support checking of just dirname, and now can be used to check paths when creating files or directories.