Add RAII listener blocking utility

* Added for ToolPanel listener and Adjuster
* Follows style of ConnectionBlocker for sigc::connection

rtgui/guiutils.cc

@@ -25,6 +25,8 @@
 #include "rtimage.h"
 #include "rtscalable.h"
 #include "multilangmgr.h"
+#include "adjuster.h"
+#include "toolpanel.h"
 
 #include <assert.h>
 
@@ -77,6 +79,34 @@ void IdleRegister::destroy()
     mutex.unlock();
 }
 
+BlockAdjusterEvents::BlockAdjusterEvents(Adjuster* adjuster) : adj(adjuster)
+{
+    if (adj) {
+        adj->block(true);
+    }
+}
+
+BlockAdjusterEvents::~BlockAdjusterEvents()
+{
+    if (adj) {
+        adj->block(false);
+    }
+}
+
+DisableListener::DisableListener(ToolPanel* panelToDisable) : panel(panelToDisable)
+{
+    if (panel) {
+        panel->disableListener();
+    }
+}
+
+DisableListener::~DisableListener()
+{
+    if (panel) {
+        panel->enableListener();
+    }
+}
+
 Glib::ustring escapeHtmlChars(const Glib::ustring &src)
 {