fixed severe bug with sending fbupdates

CHANGES

+   fixed severe bug (Const Kaplinsky)
    got patch from Const Kaplisnky with CursorPosUpdate encoding and some Docs
    sync'ed with newest RealVNC (ZRLE encoding)
    a HTTP request for tunnelling was added (to fool strict web proxies)

main.c

@@ -766,7 +766,8 @@ rfbProcessEvents(rfbScreenInfoPtr rfbScreen,long usec)
   i = rfbGetClientIterator(rfbScreen);
   cl=rfbClientIteratorNext(i);
   while(cl) {
-    if(cl->sock>=0 && (!cl->onHold) && FB_UPDATE_PENDING(cl)) {
+    if (cl->sock >= 0 && !cl->onHold && FB_UPDATE_PENDING(cl) &&
+        !sraRgnEmpty(cl->requestedRegion)) {
       if(cl->screen->rfbDeferUpdateTime == 0) {
 	  rfbSendFramebufferUpdate(cl,cl->modifiedRegion);
       } else if(cl->startDeferring.tv_usec == 0) {

rfbserver.c

@@ -1101,7 +1101,7 @@ rfbSendFramebufferUpdate(cl, givenUpdateRegion)
      sraRgnSubtract(cl->modifiedRegion,updateRegion);
      sraRgnSubtract(cl->modifiedRegion,updateCopyRegion);
 
-     /* sraRgnMakeEmpty(cl->requestedRegion); */
+     sraRgnMakeEmpty(cl->requestedRegion);
      sraRgnMakeEmpty(cl->copyRegion);
      cl->copyDX = 0;
      cl->copyDY = 0;