[winex11.drv/keyboard.c] :Some fix and new function.

[Anatoly]

Hi!

This patch adds in /dlls/winex11.drv/ new module (ucs2keysym.c).
Keyboard.c needs this module (function ucs2ketsym) for convert Unicode 
values to KeySym (See
patch). Now in function X11DRV_VkKeyScanEx have removed  FIXME,because 
function ucs2keysym returns correct keysym for wchar/

Changelog:
Add function usc2keysym to convert from WCHAR values to Keysym. And now
we have correct keycode for wchar values.