The new functions are meant to replace many uses of find_directory():
* find_paths() is supposed to be used when the directories of a certain
kind in all installation directories are needed (e.g. font
directories, add-on directory, etc.). Using this API makes code
robust wrt addition or removal of installation locations.
* find_path() is supposed to be used when files/directories associated
with a loaded program, library, or add-on need to be found (e.g. data
files or global settings).
* find_path_for_path() is similar to find_path(), but it starts from a
given path instead of an image.