Update net/mitmproxy to 2.0.1

Changes:
15 March 2017: mitmproxy 2.0.1
    * bump cryptography dependency
    * bump pyparsing dependency
    * HTTP/2: use header normalization from hyper-h2

21 February 2017: mitmproxy 2.0
    * HTTP/2 is now enabled by default.
    * Image ContentView: Parse images with Kaitai Struct (kaitai.io) instead of Pillow.
      This simplifies installation, reduces binary size, and allows parsing in pure Python.
    * Web: Add missing flow filters.
    * Add transparent proxy support for OpenBSD.
    * Check the mitmproxy CA for expiration and warn the user to regenerate it if necessary.
    * Testing: Tremendous improvements, enforced 100% coverage for large parts of the
      codebase, increased overall coverage.
    * Enforce individual coverage: one source file -> one test file with 100% coverage.
    * A myriad of other small improvements throughout the project.
    * Numerous bugfixes.

26 December 2016: mitmproxy 1.0
    * All mitmproxy tools are now Python 3 only! We plan to support Python 3.5 and higher.
    * Web-Based User Interface: Mitmproxy now offically has a web-based user interface
      called mitmweb. We consider it stable for all features currently exposed
      in the UI, but it still misses a lot of mitmproxy窶冱 options.
    * Windows Compatibility: With mitmweb, mitmproxy is now useable on Windows.
      We are also introducing an installer (kindly sponsored by BitRock) that
      simplifies setup.
    * Configuration: The config file format is now a single YAML file. In most cases,
      converting to the new format should be trivial - please see the docs for
      more information.
    * Console: Significant UI improvements - including sorting of flows by
      size, type and url, status bar improvements, much faster indentation for
      HTTP views, and more.
    * HTTP/2: Significant improvements, but is temporarily disabled by default
      due to wide-spread protocol implementation errors on some large website
    * WebSocket: The protocol implementation is now mature, and is enabled by
      default. Complete UI support is coming in the next release. Hooks for
      message interception and manipulation are available.
    * A myriad of other small improvements throughout the project.

16 October 2016: mitmproxy 0.18
    * Python 3 Compatibility for mitmproxy and pathod (Shadab Zafar, GSoC 2016)
    * Major improvements to mitmweb (Clemens Brunner & Jason Hao, GSoC 2016)
    * Internal Core Refactor: Separation of most features into isolated Addons
    * Initial Support for WebSockets
    * Improved HTTP/2 Support
    * Reverse Proxy Mode now automatically adjusts host headers and TLS Server Name Indication
    * Improved HAR export
    * Improved export functionality for curl, python code, raw http etc.
    * Flow URLs are now truncated in the console for better visibility
    * New filters for TCP, HTTP and marked flows.
    * Mitmproxy now handles comma-separated Cookie headers
    * Merge mitmproxy and pathod documentation
    * Mitmdump now sanitizes its console output to not include control characters
    * Improved message body handling for HTTP messages:
      .raw_content provides the message body as seen on the wire
      .content provides the decompressed body (e.g. un-gzipped)
      .text provides the body decompressed and decoded body
    * New HTTP Message getters/setters for cookies and form contents.
    * Add ability to view only marked flows in mitmproxy
    * Improved Script Reloader (Always use polling, watch for whole directory)
    * Use tox for testing
    * Unicode support for tnetstrings
    * Add dumpfile converters for mitmproxy versions 0.11 and 0.12
    * Numerous bugfixes


(leot)