Improve ParticipantCore test.
Add some test related macros to ParticipantCore and improve drop_*() methods.
Improve ParticipantCore test.
Fix ParticipantCore::has_any_role().
Extend ParticipantCore test with "IdentityManagement" case.
Introduce MulticastParticipantRole test.
Add Buffer::operator bool.
Add DEBUG_ERROR macro and print_debug_error() function template.
Hide information bar in main window by default.