[ptx] Better usage of fisheye images with hugin

[Mike Runge]

Pablo, Douglas,

if you're working on enhancements for creating full sphericals (e.g.
inside cropping, etc.) i just would like to remind, that there are
actually some contraints to do the job with hugin:
- load images, that are taken in portrait mode in landscape mode
(unrotated)
- use PTStitcher to stitch

Nona unfortunatly cannot be used due to the 360-0 deg bug:
http://www.panoclub.de/gallery/360-deg-bug

PTStitcher is using the default crop angle. Therefore images, that are
taken in portrait mode and loaded in portrait mode will be significantly
cropped:
http://www.panoclub.de/gallery/hugin_bug_ptstitcher

Idealy, it would be nice to:
- load the images like they are coming out of the camera
- see them right oriented according to the roll-value in hugin (idealy in
controlpointstab to)
- define the crop radius/diameter (idealy different radius for different
lenses. That would allow to use a much smaller radius for zenith an
nadir)
- use of PTStitcher/nona

Just a short summary of already discussed topics focussed on fisheye lens
usage.

best, mike