Added workaround for win32 low-level mouse hook position weirdness.

The low-level hook can report mouse positions outside the boundaries
of the screen and bogus retrograde motion.  This messes up switch on
double tap.  This change attempts to detect and suppress the bogus
events.

lib/server/CServer.h

@@ -278,6 +278,13 @@ private:
 	// whichever screen is active
 	SInt32				m_x, m_y;
 
+	// last mouse deltas.  this is needed to smooth out double tap
+	// on win32 which reports bogus mouse motion at the edge of
+	// the screen when using low level hooks, synthesizing motion
+	// in the opposite direction the mouse actually moved.
+	SInt32				m_xDelta, m_yDelta;
+	SInt32				m_xDelta2, m_yDelta2;
+
 	// current configuration
 	CConfig				m_config;