correctly detect loaded PythonQt
introduce getprop() for PythonQt/PyQt compat.
remove default arg. of Slide.showFrame()
correct missing QtCore. prefix

(now would this work?)
clearing the mouse cursor once is enough
add pythonqt_workarounds
fix labels in changed_rects_numpy_only
fix Frame pickling for PythonQt

Obviously, __getnewargs__ will not work with PythonQt.
Exact cause still unknown, but apparently PyQt
implements __new__ and passes arguments on to __init__,
while PythonQt does not.
rename _adjustViewport -> _adjustSlideViewport
add missing newline
add two PythonQt-specific workarounds

and a missing getprop(...)
fix slide moving in viewport when zooming
re-activate custom content handling
PDFInfos: fix extract_names & support Beamer frames
move stack_frames() into Presentation.addFrames()
use beamer structure for frame stacking
pdf_infos docstrings and status output
move most code into 'pdf_decanter' package
handle RMB/MMB in presentation mode
make handling PDFs without named anchors easier