open street map layer (#274)

* created OpenStreetMapLayerSample using OPEN_STREET_MAP basemap

* Converted README.md to HTML and renamed image

* Recaptured OpenStreetMapLayer.png and lightly edited README.md

* Update OpenStreetMapLayerSample.java

changed copyright to 2018

* Update OpenStreetMapLayerSample.java

removed extra newline

* Update OpenStreetMapLayerSample.java

* Changed call from addAll(mapView) to stackPane.getChildren().add(mapView)
Corrected typos in code comments
Standardized README text to match existing READMEs in Samples repo

* changed Tags heading to <H2>

Author: markjdugger

src/main/java/com/esri/samples/ogc/open_street_map_layer/OpenStreetMapLayer.png

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+/*
+ * Copyright 2018 Esri.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.esri.samples.ogc.open_street_map_layer;
+
+import javafx.application.Application;
+import javafx.scene.Scene;
+import javafx.scene.layout.StackPane;
+import javafx.stage.Stage;
+
+import com.esri.arcgisruntime.mapping.ArcGISMap;
+import com.esri.arcgisruntime.mapping.Basemap;
+import com.esri.arcgisruntime.mapping.view.MapView;
+
+public class OpenStreetMapLayerSample extends Application {
+
+  private MapView mapView;
+
+  @Override
+  public void start(Stage stage) {
+
+    try {
+      // create stack pane and application scene
+      StackPane stackPane = new StackPane();
+      Scene scene = new Scene(stackPane);
+
+      // set title, size, and add scene to stage
+      stage.setTitle("Open Street Map Sample");
+      stage.setWidth(800);
+      stage.setHeight(700);
+      stage.setScene(scene);
+      stage.show();
+
+      // create map with an OpenStreetMap basemap
+      ArcGISMap map = new ArcGISMap(Basemap.Type.OPEN_STREET_MAP, 34.056295, -117.195800, 10);
+      
+      // set the map to a map view
+      mapView = new MapView();
+      mapView.setMap(map);
+
+      // add the map view to stack pane
+      stackPane.getChildren().add(mapView);
+    } catch (Exception e) {
+      // on any error, display the stack trace.
+      e.printStackTrace();
+    }
+  }
+
+  /**
+   * Stops and releases all resources used in application.
+   */
+  @Override
+  public void stop() {
+
+    if (mapView != null) {
+      mapView.dispose();
+    }
+  }
+
+  /**
+   * Opens and runs application.
+   *
+   * @param args arguments passed to this application
+   */
+  public static void main(String[] args) {
+
+    Application.launch(args);
+  }
+
+}

src/main/java/com/esri/samples/ogc/open_street_map_layer/OpenStreetMapLayerSample.java

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+<h1>OpenStreetMap Layer</h1>
+
+<p>Add the OpenStreetMap layer to a map as a Basemap.</p>
+
+<p><img src="OpenStreetMapLayer.png"/></p>
+
+<h2>How it works</h2>
+<p>To create a map with an OpenStreetMap basemap:</p>
+<ol>
+   <li>Create an <code>ArcGISMap</code> with a <code>Basemap.Type.OPEN_STREET_MAP</code>.</li>
+   <li>Set the map to a <code>MapView</code>.</li>
+</ol>
+
+<h2>Relevant API</h2>
+
+<ul>
+   <li>ArcGISMap</li>
+   <li>Basemap</li>
+   <li>Basemap.Type</li>
+   <li>MapView</li>
+</ul>
+
+<h2>Tags</h2>
+<p>Layers</p>
+<p>OpenStreetMap</p>