Fix detecting which processes we can attach to when using Qt5 on Windows.
Fix function overwriting on Windows with Qt5.
Try harder to get into MSVC builds in release mode.

In release mode MSVC seems to use the counter-part to -Bsymbolic, with so
far no known way to disable that. This means function overwrites don't
actually work. Which is fine, we have an event-filter based fallback that
still sees most objects, but for that we must create the probe late enough,
after qApp exists.
Merge remote-tracking branch 'origin/1.3'

Conflicts:
	core/probe.cpp