Make it simpler.

[byehack]

As this is just PoW script and not recommended for production & personal use, let make it simpler for who want read the script:

• removed unused imports
• handle python-resources availability
• don't use first_flag variable
• move send_data_in_fragment to handshake
• unpack functions from class
• code polish
• main work moved to handshake function
• backend_connect for user specified rotating IPs

[cs127]

why remove the interpreter directive (#!/usr/bin/env python3)?

[byehack]

Thanks, added.

[byehack]

#61