android: make the 'more info' document accessible from the about dialog

Now that the default activity is not the viewer, but the document
browser, there is no way to show the introduction document. Add a button
to the about dialog to still show it.

Change-Id: I9252064aaaf4c49da519e17b651e0d290bc17c04

android/experimental/LOAndroid3/res/values/strings.xml

@@ -9,6 +9,7 @@
 
     <string name="about_license">Show License</string>
     <string name="about_notice">Show Notice</string>
+    <string name="about_moreinfo">More Info</string>
 
     <string name="browser_app_name">LibreOffice Browser</string>
     <string name="menu_search">Search</string>

android/experimental/LOAndroid3/src/java/org/libreoffice/LibreOfficeMainActivity.java

@@ -218,6 +218,15 @@ public class LibreOfficeMainActivity extends Activity {
             }
         });
 
+        builder.setNeutralButton(R.string.about_moreinfo, new DialogInterface.OnClickListener() {
+            @Override
+            public void onClick(DialogInterface dialog, int id) {
+                LOKitShell.sendEvent(LOEventFactory.close());
+                LOKitShell.sendEvent(LOEventFactory.load(DEFAULT_DOC_PATH));
+                dialog.dismiss();
+            }
+        });
+
         AlertDialog dialog = builder.create();
         dialog.show();
     }