octave-control @2.6.6_0: update to 2.8.0

[Schamschula (Marius Schamschula)]

octave-control has been updated to version 2.8.0:

control-2.8.0   Release Date: 2015-03-22   Release Manager: Lukas Reichlin
===============================================================================

** zero
   Compatibility fix in the C++ oct-file to support the upcoming Octave 4.0.
   (Thanks to Andreas Weber)

** isminimumphase
   Reverted changes from control-2.6.6.  According to the definition of
   Byrnes/Isidori, the function tests whether the system has asymptotically
   stable zero dynamics.  The poles are not tested.
   Note that the definition from Wikipedia is mixed up.
   For details, see the help text of the function (help @lti/isminimumphase)
   and the papers referenced therein.  (Thanks to Ulf Schaper)

** series
   Fixed a bug which gave unnecessary error messages when the function is
   called with 4 arguments.  (Thanks to Ulf Schaper)
   
** tf
   Resolved issues in MIMO state-space to transfer function conversion
   by implementing a more robust algorithm in SLICOT routine TB01ZD.
   The same algorithm is used in Octave's krylov function.
   (Thanks to Thomas Vasileiou)
   
** It is now possible to cross-compile the control package.
   (Thanks to John Donoghue)
   
** Support for 64bit indexing, i.e. Octave versions built with the --enable-64
   option.  (Thanks to Mike Miller)  

** The control package now depends on Octave version 3.8.0 or beyond.

** In order to comply with modified Octave Forge rules, the package no longer
   auto-loads.  See "help pkg" for details on auto-loading.

[michaelld (Michael Dickens)]

done in r134580.