Add setting for default of perspective / orthographic

[tincansassoc]

I find myself using the orthographic view for over 90% of my workflow, however photoscan is always defaulting to perspective view. I find this annoying because it is much more difficult to create an accurate bounding box while using the perspective view and that is one of the first steps.

This seems like a simple fix by adding setting for default of perspective / orthographic in the photoscan preferences

[tezen]

+1

...I think this improvement is "an easy one" - and a shortcut would be nice too...