First Qt5 conversion commit

Replaced PyQt4 with PyQt5 and made all adjustments necessary to make
dupeGuru start up.
Fixed occasional core dumps on exit
Implemented super() inheritance style suggested by PyQt5
Merge branch 'develop' into qt5
Updated README
Merge branch 'develop' into qt5

Conflicts:
	hscommon/desktop.py
Fixed qt5 migration for ME and PE
Merge branch 'qt5' into develop

Conflicts:
	README.md
	qtlib/about_box.py
	qtlib/reg.py
	qtlib/reg_demo_dialog.py
	qtlib/reg_submit_dialog.py