Fixes Maps4HTML#501 by restoring marker-*pngs and bumping the npm/unpkg releas… (Maps4HTML#502)

* Fixes Maps4HTML#501 by restoring marker-*pngs and bumping the npm/unpkg release version.

* Fixes Maps4HTML#501 with a README update, too.

* Fixes Maps4HTML#501 with another README update, this time to (obviously) use @latest in the CDN url.

Author: erictheise

Gruntfile.js

@@ -138,7 +138,7 @@ module.exports = function(grunt) {
             cwd: 'node_modules/leaflet/dist/images/',
             flatten: true,
             filter: 'isFile',
-            src: ['layers.png','layers-2x.png'],
+            src: ['*.png'],
             dest: 'dist/images/'
           }
         ]

README.md

@@ -12,7 +12,7 @@ defined in the MapML (Map Markup Language)
 
 Beginning with `v0.8.2`, <mapml-viewer> can be loaded from the [UNPKG content delivery network](https://unpkg.com/) –
 ```html
-<script type="module" src="https://unpkg.com/@maps4html/web-map-custom-element@0.8.2/dist/mapml-viewer.js"></script>
+<script type="module" src="https://unpkg.com/@maps4html/web-map-custom-element@latest/dist/mapml-viewer.js"></script>
 ```
 
 – or installed using npm.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@maps4html/web-map-custom-element",
-  "version": "0.8.2",
+  "version": "0.8.3",
   "description": "web-map customized built-in HTML <map> or custom <mapml-viewer>",
   "keywords": [
     "web-components",