Add macros that indicate OpDiLib's version.

Author: jblueh

include/opdi/config.hpp

@@ -25,6 +25,12 @@
 
 #pragma once
 
+/* ------------------ OpDiLib version ------------------ */
+
+#define OPDI_MAJOR 1
+#define OPDI_MINOR 7
+#define OPDI_PATCH 1
+
 /* ------------------ constants ------------------ */
 
 /* backends */