#21 Ability to provide supplemental info in case of failure

[Matt Wilson]

if(!XTESTS_TEST_ENUM_EQUAL(TT_KEYWORD, tokens[i * 2].tokenType))
{
XTESTS_TEST_PRINT_ADDITIONAL("token string: %s", csharp_keywords[i]);
}

The XTESTS_TEST_PRINT_ADDITIONAL() would create output that would be emitted along with the test results