assert_handler_c: Added small docblock for get_set_strat test.
assert_handler_c: Added empty operator(), test safe to call when strat is null.
assert_handler_c: operator() forwards to strat's on_assert().
assert_handler_c: Added real params to expected forwarded call to on_assert.
assert_handler_c: Split strat() into const, non-const props.
Pluggable assert mech reasonably complete, tested.
Refactored into modules.
Updated todo.
Added assert macros, gtest integration.
Cleared todo.

- Bashed tracing for now. Tracing has become less useful of late.