Add SpecialAttributeInterface
Add tests for SpecialAttribute
Enable special attribute only single-line convert
Add tests of Sectioni plugin implemented SpecialAttributeInterface
Implement SpecialAttributeInterface to Section plugin
Add tests for implementing SpecialAttributeInterface to Cols plugin.

Add test to Section plugin test behaving as Cols plugin
Add test to Row: adding set/get id attribute API
Add test to Cols plugin test special attributes
Enable special attributes to Cols plugin
Add tests for special attributes of multi-line convert syntax
Enable special attributes of multi-line convert syntax