simplify sorting of setof items
That is a simplification which makes the implementation use libc's qsort and memcmp to sort elements of SET OF.
- Code modified for feature
- Test suite updated with functionality tests
- There is a test suite reasonably covering new functionality or modifications
- Function naming, parameters, return values, types, etc., are consistent with other code
- This feature/change has adequate documentation added
- No obvious mistakes in the code