changes for qt5 on mac

- setShown() -> setVisible()
- qt_mac_set_menubar_icons() no longer exported, use alternative method
more qt5 mac fixes

- workaround for -psn_0 being passed in
- use fusion if plastique missing
failure to find a field should not break entire query

https://anki.tenderapp.com/discussions/ankidesktop/656-unexpected-results-on-search-with-boolean-or-operator
Merge remote-tracking branch 'ospalh/fix-unload-collection' into flake
Merge pull request #25 from ospalh/fix-unload-collection

Fix the return value of aqt.main.unloadCollection()
typo
Smaller margin.
Merge remote-tracking branch 'ospalh/ospalh-special' into ospalh-special

Conflicts:
	aqt/reviewer.py
Merge remote-tracking branch 'dae/master' into flake

Conflicts:
	aqt/__init__.py
Re-clean.
Just get the QT_VERSION_STR from the source.
Check for self.typedAnswer only after it has been set.
Redo the show answer fix by hand.
Merge remote-tracking branch 'frento/ospalh-special' into ospalh-special
Merge remote-tracking branch 'vanilla/fix-type-answer-in-comment' into ospalh-special