created overridable report() function to be used in place of print()

9unit.h

@@ -40,6 +40,7 @@ struct TestState
 	const char *context; // immediate context of current test
 	const char *full_context; // full context of current test
 	int depth; // how many tests "deep" are we?
+	void (*report)(const char *); // prints a string immediately
 };
 
 struct TestLogEntry