Added Win V-Sync/Triple buffering files.

They're not included in the actual source tree due to problems.

zsnes/src/win/vsync/readme.txt

@@ -0,0 +1,26 @@
+This is the version of winlink.cpp with vsync and triple buffering enabled
+  by default.  The big change is that originally, ZSNESw wasn't using
+  exclusive mode in full-screen and just changed the windows desktop
+  resolution and created a window the size of the resolution.  So exclusive
+  mode was added.  This file is separate from the sources since it still
+  has problems (note below).
+
+**WARNING** this will freeze the O/S if you switch video modes
+  in ZSNESw.  I cannot seem to figure out why though, but I do know that
+  when switching from full-screen to windowed will cause a create primary
+  buffer error (can't exactly see the error though), while switching
+  from full to another full will cause a different error.
+
+Problem #2: It seems like the first call to startgamefull() will cause
+  an error in setcooperativelevel with the error InvalidParams.  But it
+  also seems like the same call later in the future turns out to be okay.
+  Weird.
+
+The routines that are changed are:
+- startgame() is modified
+- startgamefull() is added (for exclusive mode)
+- DrawScreen() has been changed to add in the back buffer/swap blitter
+- initwinvideo() is also changed.
+
+Note: initwinvideo() seems to be called twice (or more?) when ZSNESw starts
+  and also once when the game starts (not sure about exiting the game though)