Two convenience functions that help enumerating the contents of a directory more easily using a callback function. Includes documentation, and the ex_dir example was enhanced to demonstrate it.
Simplified the idea of al_for_each_file() to a single al_for_each_fs_entry() function that has support for optional recursion and could be extended in the future.
Document that al_read_directory and al_for_each_fs_entry will skip over any files named '.' or '..' .
Make sure al_for_each_fs_entry() also stops iterating recursively if the callback returns false. To allow this, the whole function now returns false in this case. However, it does not use al_set_errno in this case so it can be distinguished from an error like that.
Removed any mention of the underlying implementation of al_for_each_fs_entry(). Also clarified a few points that had been missing.
Small rewording of documentation of al_for_each_fs_entry.