Improve code documentation
Move non-template abc::testing::test_case members to .cxx file
Add missing this from ABC_TRACE_FN
Merge test_case::assert_impl() and runner::log_assertion_*() into runner::log_assertion()
Move implementation of ABC_TESTING_ASSERT_*THROW*() to methods in .cxx file
Improve code documentation
Add abc::source_location
Add ABC_SOURCE_LOCATION() macro to simplify instantiation of abc::source_location
Fix code documentation
Add abc::to_str_backend specialization for abc::source_location
Use abc::source_location in place of file/line pairs in abc::testing
Add missing ABC_TRACE_FN
Improve code documentation
Use abc::source_location in abc::exception
Use ABC_TESTING_ASSERT_THROWS() instead of custom testing code in abc::testing::exception_polymorphism
Use ABC_TESTING_ASSERT_THROWS() instead of custom testing code in abc::test::exception_from_os_hard_error
Use testing-specific exception hierarchy for polymorphism tests
Update copyright years
Use abc::source_location in abc::scope_trace and abc::assertion_error
Remove abc::pointer_iterator::operator bool()

Iterators must always be compared with other iterators.