networkbench: Include ping6 and TTFB support

  Replace urlib by pycurl to get the 'Time To First Byte' responses.
  Include ping6 support
  Verbose how much package lost the connection had in case of package lost.

See merge request !1

  Replace urlib by pycurl to get the 'Time To First Byte' responses.
  Include ping6 support
  Verbose how much package lost the connection had in case of package lost.

Python 2.7.9 enabled SSL certificate verification by default (PEP476).
This commit disables certificate verification by creating
a non-verifying SSL context.

Allow to detect if instance has been processed or not.