Do not limit the client's heap space (See FLINK-934)

Similar to  FLINK-934 and https://github.com/apache/incubator-flink/pull/14 we should not limit the heap space of the job submission client to 512MB.

A user actually had the following exception while using Flink:
```
java.lang.OutOfMemoryError: Java heap space
	at eu.stratosphere.runtime.io.serialization.DataOutputSerializer.resize(DataOutputSerializer.java:243)
	at eu.stratosphere.runtime.io.serialization.DataOutputSerializer.write(DataOutputSerializer.java:87)
	at eu.stratosphere.nephele.jobgraph.JobGraph.writeRequiredJarFiles(JobGraph.java:706)
	at eu.stratosphere.nephele.jobgraph.JobGraph.write(JobGraph.java:641)
	at eu.stratosphere.nephele.ipc.RPC$Invocation.write(RPC.java:153)
	at eu.stratosphere.nephele.ipc.Client$Connection.sendParam(Client.java:469)
	at eu.stratosphere.nephele.ipc.Client.call(Client.java:689)
	at eu.stratosphere.nephele.ipc.RPC$Invoker.invoke(RPC.java:250)
	at com.sun.proxy.$Proxy1.submitJob(Unknown Source)
	at eu.stratosphere.nephele.client.JobClient.submitJobAndWait(JobClient.java:258)
	at eu.stratosphere.client.program.Client.run(Client.java:284)
	at eu.stratosphere.client.program.Client.run(Client.java:268)
	at eu.stratosphere.client.program.Client.run(Client.java:262)
	at eu.stratosphere.client.program.ContextEnvironment.execute(ContextEnvironment.java:50)
	at eu.stratosphere.example.java.wordcount.WordCount.main(WordCount.java:79)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at eu.stratosphere.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:384)
	at eu.stratosphere.client.program.PackagedProgram.invokeInteractiveModeForExecution(PackagedProgram.java:302)
	at eu.stratosphere.client.program.Client.run(Client.java:220)
	at eu.stratosphere.client.CliFrontend.executeProgram(CliFrontend.java:327)
	at eu.stratosphere.client.CliFrontend.run(CliFrontend.java:314)
	at eu.stratosphere.client.CliFrontend.parseParameters(CliFrontend.java:927)
	at eu.stratosphere.client.CliFrontend.main(CliFrontend.java:951)
```

I verified that the change resolves the problem.