Replace options struct and improve option handling about cbor

[x448]

As discussed, maybe a v1.4 before 2.0 can have this baby step before merging in CBOR tags.

1. deprecate but still support boolean encoding modes in v1.4
2. add SortMode (int) and ShortestFloat (int) as encoding options to replace encoding mode booleans.

The combination of SortMode and ShortestFloat can be used to specify these modes in v1:

• default
• Canonical
• CTAP2
• Core Deterministic Encoding Rule 2 (7049bis)
• and modes that don't have a name yet

type SortMode int

const (
	SortNone			SortMode = 0	// no sorting
	SortLengthFirst			SortMode = 1	// Old Canonical
	SortBytewiseLexical		SortMode = 2	// Bytewise Lexicographic
	SortCanonical			SortMode = SortLengthFirst
	SortCTAP2			SortMode = SortBytewiseLex	
	SortCoreDeterministic		SortMode = SortBytewiseLex
)

type ShortestFloat int

const (
	ShortestFloatNone		ShortestFloat = 0	// no change
	ShortestFloat16			ShortestFloat = 1	// float16 as shortest form of float that preserves value
	ShortestFloat32			ShortestFloat = 2	// float32 as shortest form of float that preserves value
	ShortestFloat64			ShortestFloat = 3	// float64 as shortest form of float (this may convert from float32 to float64, etc.)
)

[x448]

@fxamacker hey, I think this can be closed because of your commits today. nice work!