cardconv updated.

png images converted from gifs by IM resulted in an indexed png format. This
lead to Problems with tranparency, especially with ganijfa and hanafuda
cardsets. To circumvent these problems IM had to be advised to produce
32 bit mode rgba format.
affects android apk build process only.

scripts/cardconv

@@ -34,9 +34,15 @@ convdir() {
   mkdir -p "$2"
 
   # Convert all images
-  for i in $1/*.$ifo; do
-    convert "$i" "$2/$(basename $i .$ifo).$ofo"
-  done
+  if [ $ofo == 'png' ]; then
+    for i in $1/*.$ifo; do
+      convert "$i" "-matte" "-quality" "95" "png32:$2/$(basename $i .$ifo).$ofo"
+    done
+  else
+    for i in $1/*.$ifo; do
+      convert "$i" "$2/$(basename $i .$ifo).$ofo"
+    done
+  fi
 
   # Convert config.txt
   if [ -f $1/config.txt ]; then