Travis via fastlane

[KieranHarper]

Hi John, I think this project is great and I'm looking at things that would take even more steps away from the average developer's initial workflow.

This is a TravisCI + Fastlane combo, which in my experience it works a treat for simplifying the commands needed to build and test (without even getting into all the other delivery related goodies that are on offer). As you can see in the travis config, the advantage of using Fastlane for this purpose is that the entry point is dead simple and should make it easy to add other CI services as well.

Specifically the Fastlane script exercises all 3 test targets and also builds the watch one. If someone wants to remove a target because they're not supporting it they just delete the relevant scan step. Any more iOS devices can be easily added and I've left some examples commented out.

Lemme know what you think!