Added thumbnailers for stl & openscad

Signed-off-by: Tony Tkacik <tonydamage@gmail.com>

support/openscad-thumbnailer

@@ -0,0 +1,18 @@
+#!/bin/sh
+
+SCHEME=${4:-Tomorrow}
+
+IN_FILE="$1";
+OUTFILE="$2";
+SIZE="$3";
+
+
+
+openscad-nightly \
+   --preview \
+   --colorscheme=$SCHEME \
+   -o "$OUTFILE".png \
+   --imgsize=$SIZE,$SIZE \
+    "$IN_FILE" 2> /dev/null
+
+mv "$OUTFILE.png" "$OUTFILE"