Fixes bug with previously taken names for nodes, append a number at the ...

...end

Sample graph:

 val base = Storm.source(TraversableSpout(Seq(1, 2, 3, 4))).name("Source from a sequence")
    val a = base.map{_.toString}
    val b =  base.flatMap {
        i => List(i, i, i)
      }.name("Increase stream size by outputting copies")
      
   val c = a.either(b)
      .write(() => _ => com.twitter.util.Future.Unit)
      .map(_ -> 1L).name("Convert to tuple")
      .sumByKey(MergeableStoreSupplier.from {
        MergeableStore.fromStore[(Either[String, Int], BatchID), Long](jstore)
      }).name("Group by, sum and store to JMap")  


![output](https://f.cloud.github.com/assets/446652/1170572/6ed85594-20e2-11e3-936e-287510ccace7.png)