Output filter: Support Waf and scons, too

Thanks to John for the initial patch

BUG: 331124
FIXED-IN: 1.6.1
Make compile
Merge remote-tracking branch 'origin/1.6'

Conflicts:
	outputview/outputfilteringstrategies.cpp
Add porting note
Document returnType test
Streamline look of navigation context popup a bit

Make 'Container: ... Access: ...' string always appear after a newline
NativeAppErrorFilterStrategy: More improvements

Catch lines from QtTest lib such as:
QFATAL : FooTest::testBar() ASSERT: "index.isValid()" in file /foo/bar.cpp, line 32

Don't catch lines containing "Loc: [Unknown file(0)]"

Amend tests.