Precision-preserving number decode and conversion (#211)

This is part of dCBOR support. It decodes a number (int or float) into the best C representation. It's good for more than just dCBOR.


* Remove more stuff related to QCBOREncode_AddBytesLenOnly

* Commit beginnings so dev can be merged in

* Precision-preserving number decode

* Fix ifdefs for precise number decoding

* blank lines

* blank lines

* 65-bit negs without float HW

---------

Co-authored-by: Laurence Lundblade <lgl@securitytheory.com>
diff --git a/test/qcbor_decode_tests.h b/test/qcbor_decode_tests.h
index 0cedf43..bd0996b 100644
--- a/test/qcbor_decode_tests.h
+++ b/test/qcbor_decode_tests.h
@@ -319,6 +319,7 @@
 int32_t CBORTestIssue134(void);
 
 
+int32_t PreciseNumbersTest(void);
 
 int32_t ErrorHandlingTests(void);