(Part 2 -- trying again) Make compile warnings into errors; update some plugins; use https in web based generator

pom.xml

@@ -174,6 +174,7 @@
             <target>${java.version}</target>
             <compilerArgs>
               <arg>-Xlint:all</arg>
+              <arg>-Werror</arg>
             </compilerArgs>
           </configuration>
         </plugin>
@@ -416,7 +417,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-checkstyle-plugin</artifactId>
-          <version>2.15</version>
+          <version>2.16</version>
           <configuration>
             <configLocation>src/checkstyle/checkstyle.xml</configLocation>
             <!-- Android generated files -->

zxing.appspot.com/src/main/java/com/google/zxing/web/generator/client/Generator.java

@@ -197,7 +197,7 @@ public final class Generator implements EntryPoint {
 
   private static String getUrl(int sizeX, int sizeY, String ecLevel, String encoding, String content) {
     StringBuilder result = new StringBuilder(100);
-    result.append("http://zxing.org/w/chart?cht=qr");
+    result.append("https://zxing.org/w/chart?cht=qr");
     result.append("&chs=").append(sizeX).append('x').append(sizeY);
     result.append("&chld=").append(ecLevel);
     result.append("&choe=").append(encoding);

zxing.appspot.com/src/main/webapp/WEB-INF/appengine-web.xml

@@ -16,5 +16,5 @@
  -->
 <appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
   <application>zxing-hrd</application>
-  <version>11</version>
+  <version>12</version>
 </appengine-web-app>

zxing.appspot.com/src/main/webapp/app.yaml

@@ -1,5 +1,5 @@
 application: zxing-hrd
-version: 11
+version: 12
 runtime: python27
 api_version: 1
 threadsafe: true

zxingorg/pom.xml

@@ -61,7 +61,7 @@
       <plugin>
         <groupId>org.eclipse.jetty</groupId>
         <artifactId>jetty-maven-plugin</artifactId>
-        <version>9.3.0.RC1</version>
+        <version>9.3.0.v20150612</version>
       </plugin>
     </plugins>
   </build>