pep8 and pyflakes cleanup
Merge branch 'master' into cleanup-pr

# Via Ioannis Tziakos (2) and IoannisTziakos (1)
* master:
  add check on the tests
  remove unused change handler
  add check for the labels
  minor code layout rework
  pep8 and pyflakes
  basic test for autoview
  add a private trait
  cleanup logic to find the right editor for each trait
  make sure that auto_view capitalizes the labels similar to how traits ui is doing
  make sure autoview does not pick up private attributes
  fix `print_widget_tree` method of gui test assistant
fix pep8 and pyflakes violations at examples
fix leftover pep8 violation from the last merge
Merge pull request #44 from enthought/cleanup-pr

pep8 and pyflakes cleanup