Save screenshot as part of the test result

If a screenshot is taken, save the file name of the screenshot as part of test so reporters can access it later.
Include screenshots as attachments in junit

Write the screenshot file name in the system-out element of the junit reports
added support for async setUp/tearDown, fixed the timeouts protocol actions and added new frameParent action
updated execute so it makes the args paramter optional and added follow redirects in an attempt to fix #106
fixed a problem with generating the test report
refactored the attachment screenshots a bit
Merge branch 'candrews-patch-1' into features/v0.4

* candrews-patch-1:
  refactored the attachment screenshots a bit
  Include screenshots as attachments in junit
  Save screenshot as part of the test result
properly handling session create redirect status
updated tests
Merge branch 'features/v0.4'

* features/v0.4:
  updated tests
  properly handling session create redirect status
  refactored the attachment screenshots a bit
  fixed a problem with generating the test report
  updated execute so it makes the args paramter optional and added follow redirects in an attempt to fix #106
  added support for async setUp/tearDown, fixed the timeouts protocol actions and added new frameParent action
  Include screenshots as attachments in junit
  Save screenshot as part of the test result
version bump to 0.4.8
Merge branch 'master' of https://github.com/beatfactor/nightwatch into features/notAssertions