Some changes and fixes to projects.

- Fix exclude_patterns in the example.
- Remove canonization of paths so that symbolic links are left intact.
- Document exclude_patterns and new hidden option.

For directories not under version control:
- Will now follow symbolic links. These will be treated like normal directories transparently. Removal of canonization of paths is necessary for this.
- Add an option to include or exclude hidden files.
- Fetch files and directories, so that empty directories can be listed.