Improve boolean decoding error handling

Also more tests for boolean decoding
diff --git a/test/qcbor_decode_tests.h b/test/qcbor_decode_tests.h
index 53f6bd2..54e125a 100644
--- a/test/qcbor_decode_tests.h
+++ b/test/qcbor_decode_tests.h
@@ -308,5 +308,10 @@
 int32_t PeekAndRewindTest(void);
 
 
+/*
+Test decoding of booleans
+*/
+int32_t BoolTest(void);
+
 
 #endif /* defined(__QCBOR__qcbort_decode_tests__) */