Add Map and related components

This commit adds support for Maps using OpenStreetMaps and USGS tile
layers. It also adds a number of components related to Maps:

1. Marker: Custom markers to represent points on a map.
2. LineString: Line segments drawn on the map.
3. Polygon: Polygons to draw 2D areas on the map.
4. Circle: Draw a circle at a point with a given radius.
5. Rectangle: Polygons, but fixed corners/sides.
6. FeatureCollection: Collections of the above loaded
   from a GeoJSON file.

Change-Id: Ib2d7155094f2557e102de118d5c629abb9675086

appinventor/appengine/build.xml

@@ -99,6 +99,13 @@
         <include name="closure-library/**/*"/>
       </fileset>
     </copy>
+    <!-- Resources for Maps designer view -->
+    <copy todir="${build.war.dir}/">
+      <fileset dir="${lib.dir}">
+        <include name="leaflet/**/*"/>
+        <include name="font-awesome/**/*"/>
+      </fileset>
+    </copy>
   </target>
 
   <!-- =====================================================================

appinventor/appengine/src/com/google/appinventor/client/Images.java

@@ -1,6 +1,6 @@
 // -*- mode: java; c-basic-offset: 2; -*-
 // Copyright 2009-2011 Google, All Rights reserved
-// Copyright 2011-2012 MIT, All rights reserved
+// Copyright 2011-2017 MIT, All rights reserved
 // Released under the Apache License, Version 2.0
 // http://www.apache.org/licenses/LICENSE-2.0
 
@@ -544,4 +544,46 @@ public interface Images extends Resources {
   @Source("com/google/appinventor/images/cloudDB.png")
   ImageResource cloudDB();
 
+  /**
+   * Designer palette item: Map
+   */
+  @Source("com/google/appinventor/images/map.png")
+  ImageResource map();
+
+  /**
+   * Designer palette item: Marker
+   */
+  @Source("com/google/appinventor/images/marker.png")
+  ImageResource marker();
+
+  /**
+   * Designer palette item: Circle
+   */
+  @Source("com/google/appinventor/images/circle.png")
+  ImageResource circle();
+
+  /**
+   * Designer palette item: FeatureCollection
+   */
+  @Source("com/google/appinventor/images/featurecollection.png")
+  ImageResource featurecollection();
+
+  /**
+   * Designer palette item: LineString
+   */
+  @Source("com/google/appinventor/images/linestring.png")
+  ImageResource linestring();
+
+  /**
+   * Designer palette item: Polygon
+   */
+  @Source("com/google/appinventor/images/polygon.png")
+  ImageResource polygon();
+
+  /**
+   * Designer palette item: Rectangle
+   */
+  @Source("com/google/appinventor/images/rectangle.png")
+  ImageResource rectangle();
+
 }