Add experimental tags to a few examples & added doc in the README

Plus some typos.

examples/readme.md

@@ -8,3 +8,4 @@ The `.html` files in this folder are built by applying the templates in the `tem
 * docs: Documentation of the example. Can be markdown.
 * tags: Tags for the example index
 * resources: Additional js or css resources required by the example. This is a YAML list of URLs.
+* experimental: if true, a warning will appear on the example page mentioning the fact that it uses features not part of the API.

examples/semi-transparent-layer.html

@@ -3,8 +3,8 @@ layout: example.html
 title: Semi-Transparent Layer
 shortdesc: Example of a map with a semi-transparent layer.
 docs: >
-  This example will display a tiled MaxBox layer semi-transparently over an OSM background. The OSM layer is changed to back and white by using a CSS filter.
+  This example will display a tiled MaxBox layer semi-transparently over an OSM background. The OSM layer is changed to black and white by using a CSS filter.
-tags: "transparent, osm, tilejson"
+tags: "transparent, osm, tilejson, css"
 cloak:
   - key: pk.eyJ1IjoiYWhvY2V2YXIiLCJhIjoiY2pzbmg0Nmk5MGF5NzQzbzRnbDNoeHJrbiJ9.7_-_gL8ur7ZtEiNwRfCy7Q
     value: Your Mapbox access token from https://mapbox.com/ here

examples/webgl-points-layer.html

@@ -18,6 +18,7 @@ docs: >
   </p>
 
 tags: "webgl, point, layer, feature"
+experimental: true
 ---
 
 <div id="map" class="map"></div>

examples/worker.html

@@ -3,8 +3,9 @@ layout: example.html
 title: Worker
 shortdesc: This example should be deleted.
 docs: >
-  When you move the map, a message is sent to a worker.  In response, the woker sends a
+  When you move the map, a message is sent to a worker.  In response, the worker sends a
   message back with the version identifier.
 tags: "worker"
+experimental: true
 ---
 <div id="map" class="map"></div>