x0vncserver does not support SetDesktopSize; remove -AcceptSetDesktopSize

Add a Configuration::removeParam to support such cases.
diff --git a/common/rfb/Configuration.h b/common/rfb/Configuration.h
index d319915..6197317 100644
--- a/common/rfb/Configuration.h
+++ b/common/rfb/Configuration.h
@@ -80,6 +80,9 @@
     // - List the parameters of this Configuration group
     void list(int width=79, int nameWidth=10);
 
+    // - Remove a parameter from this Configuration group
+    bool remove(const char* param);
+
     // - readFromFile
     //   Read configuration parameters from the specified file.
     void readFromFile(const char* filename);
@@ -116,6 +119,9 @@
     static void listParams(int width=79, int nameWidth=10) {
       global()->list(width, nameWidth);
     }
+    static bool removeParam(const char* param) {
+      return global()->remove(param);
+    }
 
   private:
     friend class VoidParameter;