Merge pull request onekiloparsec#113 from vincentneo/master-aaplus-2.…

…44-cpp17

fundamental changes for building via SPM with AA+ 2.44

Preparing new version of ObjCAA

Signed-off-by: Cédric Foellmi <cedric@onekiloparsec.dev>

Simplification of schemes to obtain only one `SwiftAA` for both macOS…

… and iOS, and likewise for `ObjCAA`

Solving (at least tempirarily) an issue preventing SwiftAA to be used…

… with SwiftUI.

Adding initializer and convenience variable for coordinates at the ce…

…nter in SelenographicCoordinates struct (Moon.swift)

Fixed some new compilation error (protocol conformance) and warnings …

…associated with Swift5.

Complete reorganisation of the project to be able to offer a distribu…

…tion through all major mechanisms: Swift Package Manager, Cocoapods and Carthage.

Creation of an ObjCAA podspec

Giving access to Elliptical “Planetary Details” computations for Plut…

…o and the Sun.

Update of SwiftAA for Swift5, Xcode11 and AA+ 2.0+