Add a useful Unicode string for testing
Get the Py2.7-based http.client passing its tests
Add refactored http.client module from Py2.7 httplib

* All the http.client tests now pass on both Py2 and Py3!
  Achieved this by tweaking the test_httplib.py script from Py2.7 so
  it's more explicit about the distinction between bytes and unicode
  strings being passed into http.client (formerly httplib).

  Our http.client module won't be used on Py3 anyway, so the tests for
  Py3 are a bit redundant, but now test_httplib.py serves as
  reference documentation for how to write Py2+3 portable code using
  the http.client module from python-future.
Add html package 'backport'
Add some more useful links about Py3 and unicode handling