[Xcb] Win32 port changes

[Jeetu Golani]

Hi guys,

I've made the changes recommended by Julien and the other developers to the 
Win32 port.

Essentially:
- Initialization of the Winsock library and Cleanup is now for the calling 
application to perform instead of the library.
- Instead of checking for the WIN32 define I now look for _WIN32.
- Instead of duplicating code for the Win32 and Non-Win32 platforms as I had 
orignally done it I now have it unified within the same function and 
controlled by preprocessor directives. I would appreciate if someone can do 
an independent review to see if the code works across non-win32 platforms too 
and my changes haven't effected that.

Julien, since you've recommended most of the changes I would appreciate your 
comments. Will change the XCB wiki on the win32 port to reflect the changes a 
little later.

The code is still based on the earlier codebase I had used i.e. I haven't 
reworked it for the current tree in development. I'll do that once I have a 
little more time on my hands to do the testing et al. Right now I'm looking 
forward to my upcoming trip to Hong Kong to chill with a few pals :)

Speaking about reworking the Win32 port for the current devel tree and 
applying the changes to my git tree at github 
(git://github.com/topcat/xcb-win32.git). I am not certain (nor have I really 
tried to find out) how do I do this using git. Since I already have a repo 
setup with your earlier tree, the history, my changes thereon, how do I add 
all of your current repo to this? (sorry I know I haven't done too much 
reading on this but would appreciate a few clues :) )

Bye for now