0.2a1

- Added :setup: and :teardown: options for shell examples.
- Added :cwd: option for shell examples. Use this option to set the working
  directory in which the shell example will execute.
- Added :stderr: option flag for shell examples. Set this flag to use stderr
  output from shell example instead of stdout when comparing expected output.
- Added :post: option for shell examples. Set this option to the name of a
  callable in your fixtures module to post-process shell example output before
  comparison.
- Fixed bug in table of contents insertion of failed examples.
