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/run_tests.c b/test/run_tests.c
index c61fcef..d5948f2 100644
--- a/test/run_tests.c
+++ b/test/run_tests.c
@@ -124,6 +124,7 @@
 #ifndef QCBOR_DISABLE_PREFERRED_FLOAT
    TEST_ENTRY(HalfPrecisionAgainstRFCCodeTest),
    TEST_ENTRY(FloatValuesTests),
+   TEST_ENTRY(PreciseNumbersTest),
 #endif /* QCBOR_DISABLE_PREFERRED_FLOAT */
    TEST_ENTRY(GeneralFloatEncodeTests),
    TEST_ENTRY(GeneralFloatDecodeTests),