move iOS test dependencies & project to CocoaPods

[incanus]

Rather than using a combo of submodule (KIF), inline static library (OCMock), and included source (OHHTTPStubs).

Related: #1452, #1517

[incanus]

@jfirebaugh How are you feeling about the state of this? Probably interrelated with #1452.

[jfirebaugh]

Yeah, I would feel much better about this if #1452 landed first.

[incanus]

I think this is going to require us to integrate Travis & CocoaPods-based install. It may be doable. Another option is to check in the pre-built dependencies directly into version control, but that's going to grow our repo.

Considering we still have the SMCalloutView (plus future iOS dependencies) as submodules, it might not be worth eliminating just this one (KIF) once the npm-related submodules are removed.

[1ec5]

KIF will go away as part of #4794. We aren’t currently using either OCMock or OHHTTPStubs, since the telemetry tests were removed long ago (#2822).

[friedbunny]

This doesn’t seem relevant now. If we need to revisit the question of how to install test dependencies, let’s consider other options before settling on CocoaPods.