specfun package cleanup

[Mike Miller]

CC'ing octave-maintainers list.

On task #12153, Carnë wrote:
> Nice. I have removed them from the specfun package.

I was hesitant to remove things since this is still in the development
version. Specfun now has a few things removed that are moved into
Octave, should we make it depend on octave >= 3.8.0 to ensure upgrades
don't lose functionality? And to ensure we don't accidentally make a
release of specfun before the next Octave goes out?

> By the way, the ellipj function which is implemented in C++, used to
> also have a .m implementation as well. It performed a bit slower (not
> by much if I remember correctly), but may be possible to improve.

Thanks, I saw comments referencing ellipj.m but it didn't occur to me
to look back in svn history. I'll run some comparisons on the two and
see if it's worth it to keep the C++ one.

-- 
mike