cylinder.m function - fixed copyright

[John W. Eaton]

On 26-Nov-2007, Kai Habel wrote:

| I have implemented the cylinder function. It should be compatible with
| matlab's function, please try the example.

I added this function and checked it in, however, I see

  octave:1> [X, Y, Z] = cylinder(10:-1:0,50);
  octave:2> surf(X,Y,Z);
  error: surface::defaults: not implemented
  error: called from `surface' in file 
`/home/jwe/src/octave-trunk/scripts/plot/surface.m'
  error: evaluating assignment expression near line 36, column 7
  error: called from `surf' in file 
`/home/jwe/src/octave-trunk/scripts/plot/surf.m'

are there pending changes that are needed?

Also, the tic labels on the left y axis seem to be all smashed on top
of one another at -10, but maybe that is a gnuplot bug because we are
viewing this as a 3D graph?

Finally, I find it odd that

  [X, Y, Z] = cylinder(10:-1:0,50);

by itself opens an empty plot window.  I would expect it do only
compute the X, Y, and Z values, not display anything.

jwe