SBRational Adopts Codable Protocol

Merge pull request #86 from yosshi4486/codable

feat: Adopt Codable.

v1.6.4: Merge pull request #85 from yosshi4486/remove-intermediate-error

remove: unused an error type.

v1.6.3: Merge pull request #84 from yosshi4486/patch

refactor: remove unused implementation

v1.6.2: Merge pull request #81 from yosshi4486/#79

feat: throw error.

v1.6.1: Merge pull request #61 from yosshi4486/fix-access

fix: Access Control

Add Tree Object

Merge pull request #60 from yosshi4486/nodes-in-depth

feat: Add static method.

Remove Unrelated Files

Merge pull request #57 from yosshi4486/remove-normalization-misc

Remove files.

Fix Typo

Merge pull request #56 from yosshi4486/fix-name-typo

fix: name typo

Refactored

Merge pull request #52 from yosshi4486/grow-fraction

test: Add tests for arithmetic.

Care Overflows

Merge pull request #47 from yosshi4486/care-overflow

Care overflow