text: Title: status_code requires __ne__ to work in python 2.7.x
  Body: Quoting to the 2.7.x data model [1]
  
  "There are no implied relationships among the comparison operators. The truth of x==y does not imply that x!=y is false. Accordingly, when defining **eq**(), one should also define **ne**() so that the operators will behave as expected."
  
  So in python 2.7.x one cannot do the following
  
  browser = Browser()
  browser.visit("http://www.google.com")
  if browser.status_code != 200:
      print("ERROR")
  
  This however will work in python 3.x because the data model says **ne** will automatically invert the return code of **eq**
  
  [1] https://docs.python.org/2/reference/datamodel.html
  