Fixed #16941 - Clarified naturaltime output when the time is more than a day old.

.. versionadded:: 1.4

For datetime values, returns a string representing how many seconds,

minutes or hours ago it was -- falling back to a longer date format if the

value is more than a day old. In case the datetime value is in the future

the return value will automatically use an appropriate phrase.

minutes or hours ago it was -- falling back to the :tfilter:`timesince` 

format if the value is more than a day old. In case the datetime value is in

the future the return value will automatically use an appropriate phrase.

Examples (when 'now' is 17 Feb 2007 16:30:00):

* ``17 Feb 2007 16:25:35`` becomes ``4 minutes ago``.

* ``17 Feb 2007 15:30:29`` becomes ``an hour ago``.

* ``17 Feb 2007 13:31:29`` becomes ``2 hours ago``.

* ``16 Feb 2007 13:31:29`` becomes ``1 day ago``.

* ``16 Feb 2007 13:31:29`` becomes ``1 day, 3 hours ago``.

* ``17 Feb 2007 16:30:30`` becomes ``29 seconds from now``.

* ``17 Feb 2007 16:31:00`` becomes ``a minute from now``.

* ``17 Feb 2007 16:34:35`` becomes ``4 minutes from now``.

* ``17 Feb 2007 16:30:29`` becomes ``an hour from now``.

* ``17 Feb 2007 18:31:29`` becomes ``2 hours from now``.

* ``18 Feb 2007 16:31:29`` becomes ``1 day from now``.

* ``26 Feb 2007 18:31:29`` becomes ``1 week, 2 days from now``.

.. templatefilter:: ordinal