Implement Autofixes starting with bookend whitespace
Create AutoFix to replace dots with an ellipsis
Use appsettings with autofixes
Merge remote-tracking branch 'origin/pr/257'
Extend blacklist
Make this abstract class
More consistent objet model of fixes with checks

- each class is instantionated on load
- they get all data as parameters
- better naming of fixup methods
- see issue #257
Improve docs for autofixes (issue #257)
Add standard file headers (issue #257)
Separate AUTOFIX settings from CHECKS (issue #257)
Test editing message with fixup (issue #257)
Simplify failing check test to work with fixups (issue #257)
Document automatic fixups (issue #257)