Add script which scales splash screen down

Based on reading documentation around. This particular version
is based on the ImageMagic documentation which could be found
there:

  http://www.imagemagick.org/Usage/filter/
  http://www.imagemagick.org/Usage/filter/nicolas/

Current filter is based on measuring mean error with the current
splash screen and choosing combination of parameters which
gives minimal mean error.

release/datafiles/splash_scale.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+# Use this script to generate splash.png from splash_2x.png.
+# Supposed to give best quality image.
+#
+# Based on ImageMagic documentation, which is interesting
+# to read anyway:
+#
+#  http://www.imagemagick.org/Usage/filter
+#  http://www.imagemagick.org/Usage/filter/nicolas/
+
+convert \
+  splash_2x.png \
+  -colorspace RGB \
+  -filter Cosine \
+  -resize 50% \
+  -colorspace sRGB \
+  splash.png