Added some extra output for Matisse.
Script adjustment to force override copy
Modified error calculations following:

Walsh, E., Arnold, R., & Savage, M. K. (2013). Silver and Chan revisited.
Journal of Geophysical Research-Solid Earth, 118(10), 5500â5515.
doi:10.1002/jgrb.50386

This corrects an error in the original Silver and Chan paper, regarding
the estimation of the number of degrees of freedom in the data.

Main changes:

* Moved zndf subroutine to a separate file.
* Modified NDF calculation
* Updated documentation, version number.

Squashed commit of the following:

commit 31b0da56457a4997ffa1616a3f093b5423850fd9
Author: James Wookey <j.wookey@bristol.ac.uk>
Date:   Mon Apr 7 15:17:50 2014 +0100

    updated documentation, version number

commit eb7c68c63446a18497fc407c205398130486062b
Author: James Wookey <j.wookey@bristol.ac.uk>
Date:   Mon Apr 7 12:40:06 2014 +0100

    Modified NDF calculation after Walsh et al (JGR, 2013)

commit 458a5b679adc902da1ce3b8e3820859f7de484da
Author: James Wookey <j.wookey@bristol.ac.uk>
Date:   Mon Apr 7 12:17:39 2014 +0100

    minor code cleanup

commit 060e8385dffcc5b25b5236ed51e4f72d51aae25a
Author: James Wookey <j.wookey@bristol.ac.uk>
Date:   Mon Apr 7 12:16:28 2014 +0100

    Moved NDF out of teanby.f for further modification