Fix for 64-bit
conio: CreateFileW -> syscall.Open
conio: use parentheses for multiple import
rmdir /s can remove hidden/system/readonly files.
'rmdir /s' does not remove files under junctions
remove dos.NewFileAttr, use dos.GetFileAttributes()
mkdir/rmdir/del: with no arguments, print usage
update memo_ja.md
Merge pull request #32 from hattya/64-bit

Fix for 64-bit
Merge pull request #33 from hattya/conio

Refactor conio package
Revert "conio: use parentheses for multiple import"

This reverts commit 08610043cda15f8f63d6bbd93550920eca50a7f5.