Feature: Accessibility Tree printing

This is not quite ready, and full of terrible python, but the basics are there.   It's sort of comical how long it takes to run and the amount of commands sent to generate the output.   But I think it will be helpful with some tuning.  Any suggestions would be good to get.

It adds a pae command that prints out the accessibility tree starting from the current object.   If the current object is a UIView, it will also traverse subviews to find accessibility elements, as I *think* that's what voice over is doing.


We have a function by the same name in `fblldbbase.py`. Can we have one single unified version? Can we use `int(s, 0)` to get automatic base conversion from the text of the input?