No apparent reason to fix underlying type of PushFlags

Change-Id: I7d578b135c7a1e681a70484bba30ff1e8b33e04d
Remove commented out code

Change-Id: I1ebcffc9f1b77b9491335c13ca99090385882ec3
fixes and tests for o3tl::typed_flags

create test suite for typed_flags template.
fix the operator&= and operator|= definitions

Signed-off-by: Stephan Bergmann <sbergman@redhat.com>
Conflicts:
	include/o3tl/typed_flags_set.hxx

Change-Id: I1df9ae197889af98a2fd76ff2bc07756c7b14ced
Revert "Make VCartesianAxis::get2DAxisMainLine() truly const method."

This reverts commit 410c5bd58c36d9064a79520d5bc31cb32ead1326,
it causes CppunitTest_chart2_xshape to fail.