Fixed watchos linting errors

[benasher44]

• travis.yaml now runs pod lib lint
• Fixed up build_tests.sh to work with recent xcode tools
• Fixed some async-related test failures/flakes

[garrettmoon]

@benasher44 looks like pod lib lint passes, but pod spec lint fails with the same error :(

[garrettmoon]

Ohhh, but it may be that it's because this isn't merged. Hold off on investigating.

[benasher44]

@garrettmoon pod spec lint looks at the podspec, and downloads the code pointed to by the spec, and then it does pod lib lint. Since the pod spec is still pointing at the failing tag, that's expected. Once this is merged, you'll need to update the tag. Then, it should pass.

[benasher44]

This is also why I didn't have .travis.yaml do pod spec lint, since it'll just be looking at the same code every time :)

[garrettmoon]

@benasher44 Thanks for doing this! Let's give it a go!

[garrettmoon]

Yeah, that makes sense :)