[O] [bug] ox-org.el subtree export appears broken

[Eric Schulte]

Specifically, the title is not taken from the current heading, and
subheadings are not promoted to the top level.

Export the "Example Subtree" heading in the attached example file using
the "subtree" option to demonstrate.

Thanks,

#+Title: Subtree Export Example

* Top
** Problem
I think subtree exports are broken using the Org-mode backend.  I
would expect the subtree title to become the exported page title, and
all nested heading to be promoted to the top level, however this does
not happen.  This appears to work with other backends (confirmed with
the html backend).

** Example Subtree
With the point in this subtree I export using the =subtree= option.

*** Nested subtree one
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Donec
hendrerit tempor tellus. Donec pretium posuere tellus. Proin quam
nisl, tincidunt et, mattis eget, convallis nec, purus. Cum sociis
natoque penatibus et magnis dis parturient montes, nascetur ridiculus
mus. Nulla posuere. Donec vitae dolor. Nullam tristique diam non
turpis. Cras placerat accumsan nulla. Nullam rutrum. Nam vestibulum
accumsan nisl.

*** Nested subtree two
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Donec
hendrerit tempor tellus. Donec pretium posuere tellus. Proin quam
nisl, tincidunt et, mattis eget, convallis nec, purus. Cum sociis
natoque penatibus et magnis dis parturient montes, nascetur ridiculus
mus. Nulla posuere. Donec vitae dolor. Nullam tristique diam non
turpis. Cras placerat accumsan nulla. Nullam rutrum. Nam vestibulum
accumsan nisl.

-- 
Eric Schulte
https://cs.unm.edu/~eschulte
PGP: 0x614CA05D