message: elle.test: Add `ELLE_TEST_CASE`, to ease forcing a test name.
diff: static std::string test_binary;
  +#define ELLE_TEST_CASE(F, ...) \
  + boost::unit_test::make_test_case( \
  + boost::function<void ()>(F), \
  + BOOST_PP_SEQ_HEAD(BOOST_PP_VARIADIC_TO_SEQ(__VA_ARGS__)(#F)), \
  + __FILE__, __LINE__ ) \
  +
  #if defined(BOOST_TEST_DYN_LINK)
  # define ELLE_TEST_SUITE() \
  