Add helper functions for getting raw array and dictionary values

Add initialisers using json String/Data values

Rename to SwifterJSON

Fix minimum macOS version in the Xcode project

Upgrade podspec

Fix handling NSNumber as a number, not bool if 0 or 1

Increment version

Update to Xcode 12.2 and refactor Codable conversions to not rely on …

…JSONSerializable

Make JSON conform to Hashable

Support SPM