Hello list,

I'm not always up-to-date with the org master lately, so excuse me for
only noticing it now.

The commit 2e20cf9358deb9579ae6a22bc0deb2a772387194 and its parent broke
the following functionality for me:

|   | Items       | Dispatched             | Arrived                | HT     |
|---+-------------+------------------------+------------------------+--------|
| # | Foo bar baz | [2011-07-06 Wed 01:51] | [2011-07-09 Sat 14:00] | #ERROR |
#+TBLFM: $5=(date(<$4>) - date(<$3>))*24*60*60;%i

Before the above commit it would calculate the amount of seconds between
the Dispatched and Arrived time using
$5=(date(<$4>) - date(<$3>))*24*60*60;%i

However with the introduction of org-table-time-string-to-seconds it
broke, because [2011-07-06 Wed 01:51] would match the regexp
"\\([0-9]+\\):\\([0-9]+\\)" and be considered a duration.

I think this patch fixes this.