Add a mecanism similar to the classical errno system for reporting error

but specific to the OBITools framwork

src/obierrno.c

@@ -0,0 +1,10 @@
+/*
+ * obierrno.c
+ *
+ *  Created on: 23 mai 2015
+ *      Author: coissac
+ */
+
+
+int obi_errno;
+