Update bStats metrics version.

Apparently in 1.7 we now have to specify the plugin ID in the
constructor. So mote it be.

pom.xml

@@ -117,7 +117,7 @@
     <dependency>
       <groupId>org.bstats</groupId>
       <artifactId>bstats-bukkit</artifactId>
-      <version>1.5</version>
+      <version>1.7</version>
       <scope>compile</scope>
     </dependency>
 

src/main/java/com/garbagemule/MobArena/MobArena.java

@@ -168,7 +168,7 @@ public class MobArena extends JavaPlugin
     }
 
     private void setupMetrics() {
-        Metrics metrics = new Metrics(this);
+        Metrics metrics = new Metrics(this, 2572);
         metrics.addCustomChart(new VaultChart(this));
         metrics.addCustomChart(new ArenaCountChart(this));
         metrics.addCustomChart(new ClassCountChart(this));