Swift 5 & Xcode 10 Support

[maximedegreve]

Building doesn't work anymore with the latest version of Swift.

/usr/bin/xcrun xcodebuild -project /Users/maximedegreve/Documents/Projects/MarvelSketch-OSX/Carthage/Checkouts/swiftline/SwiftlineTests/Swiftline.xcodeproj -scheme Swiftline -configuration Release -derivedDataPath /Users/maximedegreve/Library/Caches/org.carthage.CarthageKit/DerivedData/10.2.1_10E1001/swiftline/0.5.0 ONLY_ACTIVE_ARCH=NO CODE_SIGNING_REQUIRED=NO CODE_SIGN_IDENTITY= CARTHAGE=YES archive -archivePath /var/folders/79/h65yfsmd0ml5rgqm40tzs6xm0000gn/T/swiftline SKIP_INSTALL=YES GCC_INSTRUMENT_PROGRAM_FLOW_ARCS=NO CLANG_ENABLE_CODE_COVERAGE=NO STRIP_INSTALLED_PRODUCT=NO (launched in /Users/maximedegreve/Documents/Projects/MarvelSketch-OSX/Carthage/Checkouts/swiftline)User defaults from command line:
    IDEArchivePathOverride = /var/folders/79/h65yfsmd0ml5rgqm40tzs6xm0000gn/T/swiftline
    IDEDerivedDataPathOverride = /Users/maximedegreve/Library/Caches/org.carthage.CarthageKit/DerivedData/10.2.1_10E1001/swiftline/0.5.0

Build settings from command line:
    CARTHAGE = YES
    CLANG_ENABLE_CODE_COVERAGE = NO
    CODE_SIGN_IDENTITY = 
    CODE_SIGNING_REQUIRED = NO
    GCC_INSTRUMENT_PROGRAM_FLOW_ARCS = NO
    ONLY_ACTIVE_ARCH = NO
    SKIP_INSTALL = YES
    STRIP_INSTALLED_PRODUCT = NO

Prepare build
note: Using legacy build system

=== BUILD TARGET Swiftline OF PROJECT Swiftline WITH CONFIGURATION Release ===

Check dependencies
The “Swift Language Version” (SWIFT_VERSION) build setting must be set to a supported value for targets which use Swift. Supported values are: 4.0, 4.2, 5.0. This setting can be set in the build settings editor.

** ARCHIVE FAILED **


The following build commands failed:
	Check dependencies
(1 failure)

Missing:

• Tests failing because Travis needs to be updated to work with Swift 5