Clean up of ode functions

[Rik]

10/15/16

Carlo,

I checked in your changes here
http://hg.savannah.gnu.org/hgweb/octave/rev/081a201b77c7.

I followed it up with my own cset that makes these functions closer to
complete (http://hg.savannah.gnu.org/hgweb/octave/rev/869c02fde46c).  I
have tagged remaining issues with FIXME.  Please try 'grep -n FIXME
script/ode/*.m' to find these and correct them.

--Rik