Add dmg building on MacOS, move build-related stuff to deploy/

deploy/mkicns

@@ -0,0 +1,20 @@
+#!/bin/sh
+#
+# Builds .icns file from a single .png file
+#
+
+set -e
+
+filename="${1%.*}"
+mkdir "$filename".iconset
+for i in 16 32 128 256 ; do
+    n=$(( i * 2 ))
+    sips -z $i $i "$1" --out "$filename".iconset/icon_${i}x${i}.png
+    sips -z $n $n "$1" --out "$filename".iconset/icon_${i}x${i}@2x.png
+    [[ $n -eq 512 ]] && \
+    sips -z $n $n "$1" --out "$filename".iconset/icon_${n}x${n}.png
+    (( i++ ))
+done
+cp "$1" "$filename".iconset/icon_512x512@2x.png
+iconutil -c icns "$filename".iconset
+rm -r "$filename".iconset