Update _iconconvert script.

Signed-off-by: Markus Reiter <me@reitermark.us>

extensions/ui/iconset/org.eclipse.smarthome.ui.iconset.classic/icons/_iconconvert

@@ -1,40 +1,20 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
-for file in "${1}"*.svg; do
+set -e
 
+for file in "${1}"*.svg; do
   if [[ "${file}" != 'none'* ]]; then
+    png="${file%.svg}.png"
 
-    png=`echo "${file}" | sed s/.svg/.png/`
+    # Clean up SVG file.
+    svgcleaner --indent=2 "${file}" "${file}"
 
-    # format SVG file
-    if type xmllint &>/dev/null; then
-      xmllint "${file}" -o "${file}" --pretty 1
-    else
-      echo "error: xmllint not installed" 2>1
-      exit 1
-    fi
-
-    # convert SVG file to PNG
+    # Convert SVG file to PNG.
     if [ ! -f "${png}" ]; then
-
-      if type rsvg-convert &>/dev/null; then
-
-        # dependency: librsvg
-        echo "rsvg-convert: converting ${file}"
-        rsvg-convert "${file}" -o "${png}"
-
-      elif type svgexport &>/dev/null; then
-
-        # dependency: svgexport (via npm)
-        echo "svgexport: converting ${file}"
-        svgexport "${file}" "${png}"
-
-      else
-        echo "error: no SVG converter installed" 2>1
-        exit 1
-      fi
-
+      rsvg-convert "${file}" -o "${png}"
     fi
 
+    # Losslessly minify PNG file.
+    pngout "${png}" -kbKGD
   fi
 done