This updates the homeshick check command to check for modified files.
Adds tests for modified homeshick test status.

This also moves the 'add a commit' logic in the `check a castle that is
ahead of upstream` test to a function so it can be repeated via DRY
principles.
Merge pull request #88 from squaresurf/check-for-modified-files

This updates the homeshick check command to check for modified files.
Also test exit status in check test suite
This means that the tests can partially run on machines
without expect installed.
Use double brackets to check git status output
Also use --porcelain switch
Add more tests for check (test adding folders)
Add note about the testing branch
Make Quick Install section more compact
Added contribution guidelines
Add default setup for interactive script
This makes it easier for users to try and reproduce the bug in a clean environment before reporting it.
Add link to the testing framework documentation
...and add a few linebreaks
Merge branch 'master' into development
Merge remote-tracking branch 'upstream/master'