RF: Add tree attribute to FileTreeQuery for convenience

fsl/utils/filetree/query.py

@@ -149,6 +149,7 @@ class FileTreeQuery(object):
 
             tarr[tuple(idx)] = match
 
+        self.__tree          = tree
         self.__allvars       = allvars
         self.__templatevars  = templatevars
         self.__matches       = matches
@@ -179,6 +180,14 @@ class FileTreeQuery(object):
             return {var : list(self.__allvars[var]) for var in varnames}
 
 
+    @property
+    def tree(self):
+        """Returns the :class:`.FileTree` associated with this
+        ``FileTreeQuery``.
+        """
+        return self.__tree
+
+
     @property
     def templates(self) -> List[str]:
         """Returns a list containing all templates of the ``FileTree`` that