w32-pass-lwindow-to-system does not work as expected

[Lennart Borgman <lennart.borgman.073@student.lu.se>]

When discussing AltGr I noticed that w32-pass-lwindow-to-system probably 
does not due what the author intended. The documentation is correct, no 
Start Menu is opened if the variable is nil. However I would believe 
that the author wanted to use this key in Emacs. It is however still not 
possible, the key is tighed to Explorer still.

To overcome this a low level keyboard hook must be used. A good starting 
point summary is found at 
http://www.codeproject.com/win32/AntonioWinLock.asp. Look under subtitle 
"Hooks".

This is of course applicable to the rwindow counterpart too. This also 
applies to the function w32-register-hot-key which is not able to 
register hot keys for those keys because they are already registered by 
Explorer.

I think the variables and the function should be either removed or the 
behavior corrected.