added haze removal tool

Based on the paper:
  "Single Image Haze Removal Using Dark Channel Prior" by He, Sun and Tang
using a guided filter for the "soft matting" of the transmission map

rtgui/dehaze.h

@@ -0,0 +1,47 @@
+/** -*- C++ -*-
+ *  
+ *  This file is part of RawTherapee.
+ *
+ *  Copyright (c) 2018 Alberto Griggio <alberto.griggio@gmail.com>
+ *
+ *  RawTherapee is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  RawTherapee is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with RawTherapee.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include <gtkmm.h>
+#include "adjuster.h"
+#include "toolpanel.h"
+
+class Dehaze: public ToolParamBlock, public AdjusterListener, public FoldableToolPanel
+{
+private:
+    Adjuster *strength;
+
+    rtengine::ProcEvent EvDehazeEnabled;
+    rtengine::ProcEvent EvDehazeStrength;
+    
+public:
+
+    Dehaze();
+
+    void read(const rtengine::procparams::ProcParams *pp, const ParamsEdited *pedited=nullptr);
+    void write(rtengine::procparams::ProcParams *pp, ParamsEdited *pedited=nullptr);
+    void setDefaults(const rtengine::procparams::ProcParams *defParams, const ParamsEdited *pedited=nullptr);
+    void setBatchMode(bool batchMode);
+
+    void adjusterChanged(Adjuster *a, double newval);
+    void enabledChanged();
+    void setAdjusterBehavior(bool strengthAdd);
+};
+