Updates to make smart-dispatch Python 3 compatible

[jfsantos]

I made a few updates to make smart-dispatch compatible with Python 3, namely replacing all print statement calls by the print function, converting a bytestring to a string and using open instead of file to detect if the argument of the option -f is a file. I did not do extensive testing yet but this does not break it with Python 2 or 3 when running a basic test (smart_dispatch.py -qtest launch nvidia-smi).

[coveralls]

Coverage decreased (-0.06%) to 94.473% when pulling c8e697dce63701445f30533071d60800f1391177 on jfsantos:master into c94f08e828d6deec453c054fd340e694ec0e0b9a on SMART-Lab:master.

[coveralls]

Coverage decreased (-0.06%) to 94.473% when pulling 2d97763551812c90231a03a7cdcc156c4baea65d on jfsantos:master into c94f08e828d6deec453c054fd340e694ec0e0b9a on SMART-Lab:master.

[jfsantos]

There are just a few issues on Travis, I'm going to check them out soon.