Bug in inference code

[ioana-blue]

Starting from observations from #10 I think I found a bug in infer function:

https://github.com/CoderPat/structured-neural-summarization/blob/master/train_and_eval.py#L419

Look at the parameters that are passed:

        features_file=args.train_source_file,
        labels_file=args.train_target_file,

I think those files should be the inference files not the train files. This code does inference on train files. That's why I was getting thousands of outputs for an inference file with 2 samples.