[ptx] hugin, nona, enblend on amd64

[JD Smith]

> For a partial pano
> http://wurm.wh-wurm.uni-ulm.de/~redman/gallery/panoramas/bollenwies
> 
> the results are similar however, Fulvio's acceleration beats nona
> also for partial pano's..
> 
> nona:
> real    1m47.447s
> user    1m45.101s
> sys     0m1.813s
> 
> PTStitcher (f0 acceleration):
> real    0m57.642s
> user    0m55.650s
> sys     0m0.814s
> 
> PTStitcher (no acceleration):
> real    7m8.921s
> user    7m6.806s
> sys     0m0.682s
> 
> looks like I should add the approximation algorithm to nona as well :)


I thought nona was just another front-end to the panotools lib which
skipped some of the more brain-dead "mapping unused pixels" which the
source-unavailable PTStitcher apparently was doing.  Shouldn't nona be
able to call the accelerated panotools lib without any further
modification, for a *huge* speedup?  Looks like optimizing enblend
should now be the focus...

BTW, have you tested the speedup using multi-layer TIFF from
nona->enblend as patched by Edouard Gomez for reading MLTs?

JD