Merge branch 'mh/string-list'

* mh/string-list: api-string-list.txt: initialize the string_list the easy way string_list: add a function string_list_longest_prefix() string_list: add a new function, string_list_remove_duplicates() string_list: add a new function, filter_string_list() string_list: add two new functions for splitting strings string_list: add function string_list_append_nodup()