ctf_member is now linked list

This enables us to store the members of unions and structs.
Replaced info with kind in the string converting function

This makes a lot more sense - it removes the duplicity when compared to the
ctf_info_to_kind function. Also it is better suited for this compilation unit
as it is truly a kind-related function.
Renamed the ctf_info_to_kind function to ctf_kind_from_info

The name is more suitable for the kind-centric nature of the source file.