Merged master into gtk3, fixed three conflicts.

rtengine/utils.h

@@ -16,8 +16,9 @@
  *  You should have received a copy of the GNU General Public License
  *  along with RawTherapee.  If not, see <http://www.gnu.org/licenses/>.
  */
-#ifndef _SIMPLEUTILS_
-#define _SIMPLEUTILS_
+#pragma once
+
+#include <type_traits>
 
 namespace rtengine
 {
@@ -35,5 +36,10 @@ void rotate (unsigned char* img, int& w, int& h, int deg);
 void hflip (unsigned char* img, int w, int h);
 void vflip (unsigned char* img, int w, int h);
 
+template<typename ENUM>
+typename std::underlying_type<ENUM>::type toUnderlying(ENUM value)
+{
+    return static_cast<typename std::underlying_type<ENUM>::type>(value);
+}
+
 }
-#endif