Join using bcvars

Not working
```
21:55:27,311 INFO  eu.stratosphere.nephele.client.JobClient                      - 02/20/2014 21:55:26:	CHAIN DataSource(CSV Input (,)) -> Map (eu.stratosphere.example.java.relational.HandwrittenBroadcastJoin$ToUserObject) (1/1) switched to FAILED
java.lang.NullPointerException
	at eu.stratosphere.example.java.relational.HandwrittenBroadcastJoin$ToUserObject.map(HandwrittenBroadcastJoin.java:131)
	at eu.stratosphere.example.java.relational.HandwrittenBroadcastJoin$ToUserObject.map(HandwrittenBroadcastJoin.java:1)
	at eu.stratosphere.api.java.operators.translation.PlanMapOperator$ReferenceWrappingMapper.map(PlanMapOperator.java:68)
	at eu.stratosphere.api.java.operators.translation.PlanMapOperator$ReferenceWrappingMapper.map(PlanMapOperator.java:1)
	at eu.stratosphere.pact.runtime.task.chaining.ChainedMapDriver.collect(ChainedMapDriver.java:71)
	at eu.stratosphere.pact.runtime.task.DataSourceTask.invoke(DataSourceTask.java:211)
	at eu.stratosphere.nephele.execution.RuntimeEnvironment.run(RuntimeEnvironment.java:345)
	at java.lang.Thread.run(Thread.java:744)
```