Swift 4

[intellitour]

Conversion to Swift 4.

[intellitour]

Resolves #5

[Edudjr]

@intellitour Thank you for taking a time on this issue!
However, the tests did fail on travis :/

Testing failed:
“Swift Language Version” (SWIFT_VERSION) is required to be configured correctly for targets which use Swift. Use the [Edit > Convert > To Current Swift Syntax…] menu to choose a Swift version or use the Build Settings editor to configure the build setting directly.
** TEST FAILED **
The following build commands failed:
Check dependencies
(1 failure)

I can't take a look on it right now, but I think it is because of the osx image on the config file:

{
"osx_image": "xcode8.1",
"language": "objective-c",
"xcode_workspace": "Example/TLCustomMask.xcworkspace",
"xcode_scheme": "TLCustomMask-Example",
"xcode_sdk": "iphonesimulator10.1",
"script": [
"xcodebuild test -workspace Example/TLCustomMask.xcworkspace -scheme TLCustomMask-Example -destination 'platform=iOS Simulator,name=iPhone 7,OS=10.1' ONLY_ACTIVE_ARCH=NO | xcpretty"
],
"os": "osx"
}

I hope I can get into this until the end of the week.