added anomaly example for opf clients

I created a new directory under examples/opf/clients/hotgym_anomaly that performs the same experiment as 'examples/opf/experiments/anomaly/temporal/hotgym'. It uses the hotgym dataset to compute an anomaly score for each record. To run the example use:

python $NUPIC/examples/opf/clients/hotgym_anomaly/hotgym_anomaly.py <anomalyThreshold>

where "anomalyThreshold" is a value between 0 and 1 over which the client will assume the input is an anomaly and will print out a message accordingly. If no value is given, a default value of 0.5 is used.