Support UTF-8 filename in Windows

This lua library is for windows (mingw) only . It's similar to lfs but support utf-8 filename.

• lfs.dir ==> winfile.dir
• lfs.currentdir ==> winfile.currentdir
• lfs.chdir ==> winfile.chdir
• lfs.touch ==> winfile.touch
• lfs.mkdir ==> winfile.mkdir
• lfs.rmdir ==> winfile.rmdir
• lfs.attributes ==> winfile.attributes
• os.remove ==> winfile.remove
• os.rename ==> winfile.rename
• os.execute ==> winfile.execute
• os.getenv ==> winfile.getenv
• loadfile ==> winfile.loadfile
• dofile ==> winfile.dofile
• io.open ==> winfile.open
• io.popen ==> winfile.popen
• winfile.shortname : Get the shorname of the path.
• winfile.personaldir : Get My Document dir.