Tests and documentation for CBOR Sequences (#46)

CBOR Sequences, RFC 8742, were always supported. This PR just adds documentation explaining how. It also adds regression tests.
diff --git a/test/run_tests.c b/test/run_tests.c
index 5c0abe3..ac2ab78 100644
--- a/test/run_tests.c
+++ b/test/run_tests.c
@@ -104,6 +104,7 @@
     TEST_ENTRY(SetUpAllocatorTest),
     TEST_ENTRY(SimpleValuesIndefiniteLengthTest1),
     TEST_ENTRY(EncodeLengthThirtyoneTest),
+    TEST_ENTRY(CBORSequenceDecodeTests),
 #ifndef     QCBOR_CONFIG_DISABLE_EXP_AND_MANTISSA
     TEST_ENTRY(EncodeLengthThirtyoneTest),
     TEST_ENTRY(ExponentAndMantissaDecodeTests),