This changes expect and unexpected to receive the reason text as a
template argument, allowing the std::string conversion of char const*
parameters to take place only if the condition evaluates to false. This
cuts all calls to malloc and free on tests that pass.
Unit tests that wish to spawn threads for testing concurrency may now do so
by using unit_test::thread as a replacement for std::thread. These threads
propagate unhandled exceptions to the unit test, and work with the abort on
failure feature.
* Some runner member functions are now thread-safe.
* De-inline and tidy up declarations and definitions.
* arg() interface allows command lines to be passed to suites.
* Header-only!
* No external dependencies or other beast modules
* Compilation options allow for:
- Stand-alone application to run a single test suite
- Stand-alone application to run a set of test suites
- Global suite of tests inline with the host application
- Disable test suite generation completely
* Existing tests reworked to use the new classes
