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...

tools/generateSourceTarball

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+
+if [[ ! "$1" ]]; then
+  printf "%s\n" "Usage: $0 <hg tag>" "Example: $0 4.0.10"
+  exit
+fi
+
+hg update "$1"
+tools/generateReleaseInfo
+mkdir rawtherapee-"$1"
+mv ReleaseInfo.cmake rawtherapee-"$1"
+hg archive -X ".hg*" -X "rtgui/config.h" -X "rtgui/version.h" -X "rtdata/rawtherapee.desktop" rawtherapee-"$1".tar
+tar -rf rawtherapee-"$1".tar rawtherapee-"$1"/ReleaseInfo.cmake
+xz -z -9e rawtherapee-"$1".tar
+rm -r rawtherapee-"$1"
+hg update