Partially solving issue 1788: "Crashing during processing of queue"

It also correct a bug of wrong image orientation (was wrong in the File Browser while good in the Editor tab)

This patch also introduce several speed optimizations like:
   - switch between File Browser and Editor tab in Single Editor mode
   - asynchronous computation of the Batch Queue's thumbnails
   - quick start of RT even with a huge queue
   - less GUI overhead when applying a profile to multiple thumbs in the File Browser

rtgui/pparamschangelistener.h

@@ -26,9 +26,18 @@
 class PParamsChangeListener {
 
     public:
+        virtual     ~PParamsChangeListener() {}
         virtual void procParamsChanged (rtengine::procparams::ProcParams* params, rtengine::ProcEvent ev, Glib::ustring descr, ParamsEdited* paramsEdited=NULL) {}
         virtual void clearParamChanges () {}
 };
 
+class BatchPParamsChangeListener {
+
+    public:
+        virtual     ~BatchPParamsChangeListener() {}
+        virtual void beginBatchPParamsChange(int numberOfEntries) {}
+        virtual void endBatchPParamsChange() {}
+};
+
 #endif