Updating object file attirbutes

In all object files (in iperf_output), removed declaration of __class__

TCP_Test:
- removed calls to basic_utils statistics functions. Now using built-in
statistics module (functions are named pstdev and media)

TCRT_Test:
- added some documentation to Hop and Ping class

basic_utils:
- removed statistical functions (now using built-in statistical
functions)