Keybord support Added

* Implemented 'cellKb*' functions from 'sys_io' module, which are part
of the libkb library.

* Added corresponding entries in the 'Config > Settings' menu to change
the handler of the keyboard. Supported handlers: Windows, Null.

INFO: This keyboard library is *very* experimental and I am aware of
some bugs. There will be improvements soon.

rpcs3/Emu/System.cpp

@@ -261,6 +261,7 @@ void Emulator::Stop()
 	//SysCallsManager.Close();
 	GetIdManager().Clear();
 	GetPadManager().Close();
+	GetKeyboardManager().Close();
 	GetCallbackManager().Clear();
 	UnloadModules();