Change wording for Comparator doc a little
Make Matcher#mean public
Add redcarpet and yard-redcarpet-ext to dev dependencies
Remove guard test customization
Add Configuration documentation
Update Dataset documentation

- make Dataset#obj= private
- show private methods in documentation
- remove Dataset#database_type
Elaborate a bit more in Dataset documentation
Update Field#ruby_type from Sequel code
Update Field documentation
Update FieldSet documentation
Add ResultSet documentation
Merge branch 'master' of https://github.com/coupler/linkage
fix test for updated d-levenshtein parameters