Use Gonzales PE to parse *.scss files
Sass: Add tests for scss syntax
Sass: Support sorting in *.scss files
Update tests for sort-order
Clean up
Update gonzales to v2.0.0-rc0

– Use new method names
– Allow processing of *.scss files
– Check syntax name (css or scss)
- Use one `include` node for both `@include` and `@extend`
– Update tests
Less: Add tests for sort-order option
Update README

Add examples of:
- sorting properties in *.scss files
- using keywords (`$variable`, `$include` and `$import`) in sort-order config.
Sort order: Remove unnecessary test

We should not change code while sorting.
If we want to replace delimeters, it should be done with another module,
but not sort-order.
Less: Add test for csscomb/csscomb#225