Feature to drag a file from Windows (client) to Mac (server):

- changed the size of the window for dragging on Mac to 3 by 3 pixels.
- on server side, use a new thread to write file to the drop directory.

src/lib/synergy/CPlatformScreen.cpp

@@ -20,7 +20,8 @@
 
 CPlatformScreen::CPlatformScreen(IEventQueue* events) :
 	IPlatformScreen(events),
-	m_draggingStarted(false)
+	m_draggingStarted(false),
+	m_fakeDraggingStarted(false)
 {
 }