Add support for day count dates, RFC 8943 (#106)

This addresses #98 
diff --git a/test/qcbor_encode_tests.h b/test/qcbor_encode_tests.h
index ae64f7d..69f694a 100644
--- a/test/qcbor_encode_tests.h
+++ b/test/qcbor_encode_tests.h
@@ -125,7 +125,8 @@
 
 
 /*
- Encodes most data formats that are supported */
+ * Tests Encoding most data formats that are supported.
+ */
 int32_t EncodeDateTest(void);