Pipette and "On Preview Widgets" branch. See issue 227

The pipette part is already working quite nice but need to be finished. The widgets part needs more work...

rtgui/ppversion.h

@@ -0,0 +1,31 @@
+#ifndef _PPVERSION_
+#define _PPVERSION_
+
+// This number has to be incremented whenever the PP3 file format is modified or the behaviour of a tool changes
+#define PPVERSION 317
+#define PPVERSION_AEXP 301 //value of PPVERSION when auto exposure algorithm was modified
+
+/*
+  Log of version changes
+   317  2014-01-19
+		changes to behaviour of LC curve, Issue 2209
+   315  2013-12-12
+		add LH et HH curve to lab mode
+   313  2013-11-19
+		addd CL curve to lab mode
+   312  2013-11-08
+	  added numerous changes to [channel mixer]
+   311  2013-11-07
+      [Gradient] new tool (gradient/graduated filter
+      [PCVignette] new tool (vignette filter)
+
+   310  2013-09-16
+      Defringing /Threshold - changed calculation, issue 1801
+
+   307  2013-03-16
+      [Perspective] Horizontal and Vertical changed from int to double
+      added  [Directional Pyramid Denoising] Method, Redchro, Bluechro
+      added [RGB Curves] LumaMode
+ */
+
+#endif