Implementing view

[Jordi Gutiérrez Hermoso]

While attempting to run some old Matlab code of mine, I ran across
scripts/plot/view.m and its partial implementation. This seemed like
low-lying fruit, so I started implementing it fully, but I'm a little
confused about view matrices.

Matlab behaves something like this, according to help I got in the
#octave channel:

     http://matlab.pastebin.com/1kup33S5
     http://matlab.pastebin.com/g6K3eFTm

I've been trying to figure out exactly what is it doing. I can
understand the rotation part of the matrix, but why is there also a
translation, and why does this translation change if you change the
azimuth and elevation? If someone can figure this out, please let me
know.

Thanks,
- Jordi G. H.