reading NEWS from installed package

[Carnë Draug]

Hi

I have modified the news function so one can also access the NEWS file
from installed package (patch
https://savannah.gnu.org/patch/index.php?7660).

I have one question however. Currently there is no standard to where a
package should have its NEWS file (when it does). The only thing I see
is that the pkg function looks for a ChangeLog file at the root of the
package and if it exists, places it into the 'packinfo' of that
package. By looking into all the packages in octave-forge, I see two
cases:

  * a ChangeLog file in the root of the package
  * a NEWS file in the doc directory

My changeset supports the second case but could easily be modified for
other another behavior (even to try both cases). I prefer the idea of
the NEWS file to be consistent with octave (but not sure if it would
go in the doc or in the root of the package).

Carnë