Toy_VM and Toy_Stack are working and tested, read more

At this point, only a minimal number of operations are working, and
after running any kind of source code, the 'result' is simply left on
the VM's stack. Still, it's awesome to see it reach this point.

source/toy_value.h

@@ -54,3 +54,5 @@ typedef struct Toy_Value {
 #define TOY_VALUE_IS_TRUTHY(value) Toy_private_isTruthy(value)
 TOY_API bool Toy_private_isTruthy(Toy_Value value);
 
+#define TOY_VALUE_IS_EQUAL(left, right) Toy_private_isEqual(left, right)
+TOY_API bool Toy_private_isEqual(Toy_Value left, Toy_Value right);