[Document] Change '__repr__' to new style

Author: mpsonntag

odml/doc.py

@@ -42,8 +42,8 @@ def __init__(self, author=None, date=None, version=None, repository=None, oid=No
         self._origin_file_name = None
 
     def __repr__(self):
-        return "<Doc %s by %s (%d sections)>" % (self._version, self._author,
-                                                 len(self._sections))
+        return "Document %s {author = %s, %d sections}" % \
+               (self._version, self._author, len(self._sections))
 
     @property
     def oid(self):