[ptx] shear parameters are ignored

[Michal Novotny]

Hi all

I posted mail about this problem few month ago but there was no answer.
I looked into the code and found out that:

1)
There is probably bug at Panorama.cpp:1747 where should be getShear().y 
instead of getShear().x for parameter t.

2)
I just couldn't find any place in the code, where shear parameters are 
used for stitching.

If you use g,t parameters you can't get same result from 
PTStitcher(PTMender) and nona. Is this known bug?

Michal