Set Bukkit dependency to R2.1.

That's the current CraftBukkit++ version.

pom.xml

@@ -49,7 +49,7 @@
     <dependency>
       <groupId>org.bukkit</groupId>
       <artifactId>bukkit</artifactId>
-      <version>1.2.5-R1.2-SNAPSHOT</version>
+      <version>1.2.5-R2.1-SNAPSHOT</version>
     </dependency>
 
     <!-- Archive reading library for snapshots -->