Integrate OTPKit

[aaronbrethorst]

Let's start getting OTPKit integrated into OneBusAway. Here's what needs to happen:

• Add OTPKit as a package in Apps/shared/app_shared.yml (I recommend a local package for the moment to make it easier to change OTPKit and have those changes show up in OBA)
• Add OTPKit as a package dependency in OBAKit/project.yml
• Create a new tripPlannerService property in OBAKit/Application.swift of type TripPlannerService?
• Add a new function called refreshServices() to OBAKit/Application.swift, which creates a new instance of TripPlannerService if the new region supports OTP (see the similar function in CoreApplication.swift to get an idea of how this should work)
• Override open func regionsService(_ service: RegionsService, willUpdateToRegion region: Region) in OBAKit/Application.swift and call refreshServices() from it
• Add a button to the UI somewhere that presents the UI from OTPKitDemo as a modal inside of OBA and iterate til it works!