DataField/FileReader: delete copy constructor instead of deriving Item from NonCopyable
DataField/FileReader: use STL's std::sort() instead of qsort()
DataField/ComboList: don't derive from NonCopyable

We already deleted the copy constructors.  Nothing else to do.
DataField/ComboList: rename attributes, no CamelCase
DataField/ComboList: convert anonymous enum to constexpr int
DataField/ComboList: use STL's std::sort() instead of qsort()
DataField/Enum: add std::swap() overload

Optimize the std::sort() call.
DataField/Enum: delete copy constructor instead of deriving Entry from NonCopyable
DataField/FileReader: rename attributes, no CamelCase