[O] New exporter and dates in tables

[Bernt Hansen]

Hi Nicolas,

I just noticed that the new exporter does not export inactive timestamps
in table columns.  This is now controlled by the option <:t

I think this is a change from the old exporter (but I'm not sure it's
really wrong).

I have subtrees with inactive timestamps in the text indicating when
something occurred.  I normally don't want to export these.  But I think
any table data that includes inactive timestamps should be an exception
to this ... otherwise you get output tables with blank cells where the
meaningful timestamp data would be.  Exporting part of a data table
doesn't really make a lot of sense.

For now I need to delete the inactive timestamps in my running text and
enable export of inactive timestamps to get the same result I did with
the old exporter -- but I lose some of my meta data about when tasks
were created in this case.

ie.

| Date             | Amount     |  Item |
|------------------+------------+-------|
| [2013-04-04 Thu] | Lunch      | 12.50 |
| [2013-04-06 Sat] | Parking    |  6.00 |
| [2013-04-07 Sun] | Train Fair | 14.30 |

exports with no data in column 1 when I have

:PROPERTIES:
:EXPORT_OPTIONS: toc:nil <:nil
:END:

Thanks,
Bernt