Add tests for printing numbers using a compile time replacement spy

If Unity core is compiled with UNITY_OUTPUT_CHAR = putcharSpy, these tests
  will run, otherwise they are ignored and print a message
 Includes an implementation of putcharSpy, which allows checking the I/O
  from Unity during a test. Follows closely from the Fixture spy
 Tricky macros determine if putcharSpy is injected

test/tests/testparameterized.c

@@ -5,8 +5,11 @@
 ========================================== */
 
 #include <setjmp.h>
+#include <stdio.h>
 #include "unity.h"
 
+int putcharSpy(int c) {return putchar(c);} // include passthrough for linking tests
+
 #define TEST_CASE(...)
 
 #define EXPECT_ABORT_BEGIN \