[ptx] fisheye projection

[Glenn Barry]

I'd love to see Molleweide and Eckert IV as well
John Bäckstrand wrote:

> Ed Halley wrote:
> 
>> After this lovely example by "dmgerman" posted on Max Lyons' forums, I
>> would like to re-iterate my desire for additional native projections in
>> Hugin/Nona.  I don't care if PTStitcher doesn't have it.  Besides my
>> desire to do this directly on Linux, this is also the kind of feature
>> which can set Nona apart from the old closed-source PTStitcher.
> 
> 
> I can only second this!
> 
> ---
> John Bäckstrand
>