Added example

*  Added example that uses unity test fixture

examples/example_2/test/test_runners/all_tests.c

@@ -0,0 +1,12 @@
+#include "unity_fixture.h"
+
+static void RunAllTests(void)
+{
+  RUN_TEST_GROUP(ProductionCode);
+  RUN_TEST_GROUP(ProductionCode2);
+}
+
+int main(int argc, char * argv[])
+{
+  return UnityMain(argc, argv, RunAllTests);
+}