1. Changing extension of files with binary data to .bin.
2. Running separate benchmark for each query according to numElements in their
result.

1. Exporting query and result byte slices inside SubGraph so that they are
written to file when we write the SubGraph to file after gobencoding it.
2. Added benchmark test to benchmark ToJSON and ToProtocolBuffer methods for
actors and directors query for 10,100 and 1000 entities in the result.