[ptx] Separate Optimizer/Stitcher Package?

[JD Smith]

The creation of an optimizer and stitcher completely separate from
PTOptimizer/PTStitcher is a real achievement, which I think would have
great impact outside of the hugin project.  Since these have so many
fewer dependencies than hugin, does it make sense to split them off into
their own package?  Assuming they are both drop-in replacements (except
faster and with source available), I know many users of PanoTools would
benefit from their wide availability, e.g. those with a large collection
of control script files already in hand.  It would also be good
advertisement for the capabilities hugin, though I suspect the other
front-ends would catch on to the speed-up techniques and implement them
themselves.  

Another advantage of splitting them out is that the community would be
free to tinker in a way they haven't been able to before, for instance
implementing an XML-based script format, or creating new seaming
algorithms.  Though this was always a possibility before, without the
"front-ends" to drive the underlying libpano code, it wasn't a terribly
useful exercise.

JD