added sprites for high dpi screens

README.md

@@ -73,4 +73,5 @@ cp /home/aeduser/data_dir/aed_poland.csv /var/www/html/aed_poland.csv
 nvm use 8
 npm install -g @mapbox/spritezero-cli
 spritezero --ratio 1 ./src/map_style/sprite ./src/marker_icons/
+spritezero --ratio 2 ./src/map_style/sprite@2x ./src/marker_icons/
 ```

src/map_style/sprite@2x.json

@@ -0,0 +1,30 @@
+{
+  "marker_customers": {
+    "height": 100,
+    "pixelRatio": 2,
+    "width": 100,
+    "x": 0,
+    "y": 0
+  },
+  "marker_default": {
+    "height": 100,
+    "pixelRatio": 2,
+    "width": 100,
+    "x": 100,
+    "y": 0
+  },
+  "marker_no": {
+    "height": 100,
+    "pixelRatio": 2,
+    "width": 99,
+    "x": 0,
+    "y": 100
+  },
+  "marker_private": {
+    "height": 100,
+    "pixelRatio": 2,
+    "width": 100,
+    "x": 99,
+    "y": 100
+  }
+}