0.9.1

Changelog

1339165 Add a new 'include.restricted' check (#7)
e592a29 Add an --errors-only command line option
aa77094 Document the configuration file
febfd2b Fix 'include.exists' name
b8173a9 Implement String() for Checks (#5)
89f340d Rename 'includes' to 'include.exists' (#6)
bc942d3 Use %q to consistently quote string values (#8)