Automatic lossless refresh

Resend pixel perfect copies of areas that were previously sent
using a lossy encoder. This is done when there is no normal update
to send, and no congestion.
diff --git a/common/rfb/TightJPEGEncoder.cxx b/common/rfb/TightJPEGEncoder.cxx
index 7bb6126..385207f 100644
--- a/common/rfb/TightJPEGEncoder.cxx
+++ b/common/rfb/TightJPEGEncoder.cxx
@@ -64,7 +64,7 @@
 
 
 TightJPEGEncoder::TightJPEGEncoder(SConnection* conn) :
-  Encoder(conn, encodingTight, EncoderUseNativePF, -1),
+  Encoder(conn, encodingTight, (EncoderFlags)(EncoderUseNativePF | EncoderLossy), -1),
   qualityLevel(-1), fineQuality(-1), fineSubsampling(subsampleUndefined)
 {
 }