Remove unnecessary windows.h include which was used to get InterlockedIncrement for threadsafe interfaces.

I fixed the implementation of threadsafe addref and release for windows to not require it so people no longer
need to include windows.h whenever you are using a threadsafe interface.

mailnews/base/src/nsMsgCopyService.cpp

@@ -24,11 +24,6 @@
 #include "nsIMessage.h"
 #include "nsIMsgFolder.h"
 
-#ifdef XP_PC
-#include <windows.h>
-#endif 
-
-
 typedef enum _nsCopyRequestType
 {
     nsCopyMessagesType = 0x0,

mailnews/base/src/nsUrlListenerManager.cpp

@@ -19,10 +19,6 @@
 #include "msgCore.h" // for pre-compiled headers...
 #include "nsUrlListenerManager.h"
 
-#ifdef XP_PC
-#include <windows.h>    // for InterlockedIncrement
-#endif
-
 nsUrlListenerManager::nsUrlListenerManager() :
     mRefCnt(0),
     m_listeners(nsnull)