Reenable GWT unit testing, using 2.8.0-SNAPSHOT.

pom.xml

@@ -41,17 +41,21 @@
     <url>http://github.com/samskivert/jmustache</url>
   </scm>
 
+  <properties>
+    <gwt.version>2.8.0-SNAPSHOT</gwt.version>
+  </properties>
+
   <dependencies>
     <dependency>
       <groupId>com.google.gwt</groupId>
       <artifactId>gwt-dev</artifactId>
-      <version>2.7.0</version>
+      <version>${gwt.version}</version>
       <scope>test</scope>
     </dependency>
     <dependency>
       <groupId>com.google.gwt</groupId>
       <artifactId>gwt-user</artifactId>
-      <version>2.7.0</version>
+      <version>${gwt.version}</version>
       <scope>test</scope>
     </dependency>
     <dependency>
@@ -101,6 +105,9 @@
             <arg>-Xlint:-serial</arg>
             <arg>-Xlint:-path</arg>
           </compilerArgs>
+          <excludes>
+            <exclude>**/super/**</exclude>
+          </excludes>
         </configuration>
       </plugin>
 
@@ -119,14 +126,10 @@
         </configuration>
       </plugin>
 
-<!-- disabled due to src/main/gwt related hoseage
       <plugin>
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>gwt-maven-plugin</artifactId>
-        <version>2.7.0</version>
-        <configuration>
-          <mode>htmlunit</mode>
-        </configuration>
+        <version>${gwt.version}</version>
         <executions>
           <execution>
             <goals>
@@ -134,8 +137,10 @@
             </goals>
           </execution>
         </executions>
+        <configuration>
+          <mode>htmlunit</mode>
+        </configuration>
       </plugin>
--->
 
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>