[ptx] smartblend workout

[Luca N Vascon]

Workout to use it to build 360x180 panoramas.
Simply build  the psd without feather from the same pictures, and use Eric 
Krause tool to export all layers in tiffs, to shift the whole layers of some 
degrees and extract tiffs a second time.
Or generate them with ptgui, already shifted.
Blend the 2 resulting panos with smartblend
Use again panotools gui to stack together the two equirect and output a 
layered PSD.
Nice surprise, smartblend did two different works/interpretations to error, 
allowing me to decide with layer masks...
Why all this???
Try to stitch the results of Agnos eventcam (3 fisheye pictures) I 
invented...
In "tight" spaces is masochism.
For me, it is useful.