Finished support for TightVNC protocol extensions in the server code. Now "no authentication" case is handled correctly.

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@670 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/common/rfb/CapsList.h b/common/rfb/CapsList.h
index b8fb8e8..a267e93 100644
--- a/common/rfb/CapsList.h
+++ b/common/rfb/CapsList.h
@@ -48,6 +48,11 @@
     // Current number of capabilities in the list.
     int getSize() const { return numEnabled(); }
 
+    // Does the list include nothing more than one particular capability?
+    bool includesOnly(rdr::U32 code) {
+      return (numEnabled() == 1 && getByOrder(0) == code);
+    }
+
     // Add capability ("standard" vendor).
     void addStandard(rdr::U32 code, const char *name);
     // Add capability (TightVNC vendor).