return file objects instead of paths

- don't call property as method

src/dir/album.py

@@ -10,7 +10,7 @@ class Album(Directory):
     @property
     def all_files(self) -> list:
         # todo: handle unexpected dirs
-        return [file.path for file in self.contents]
+        return self.contents
 
     def populate(self, log: Log) -> list:
         contents = list()

src/dir/directory.py

@@ -35,7 +35,7 @@ class Directory(ABC):
         files = list()
         for c in self:
             # todo: handle unexpected files
-            files += c.all_files()
+            files += c.all_files
         return files
 
     @property