Allow setting access token programmatically

[1ec5]

As of 892f1e5 for #3, this library uses Directions.shared, which automatically reads the access token from the Info.plist. But if the developer needs to specify the access token programmatically, they’re out of luck. Plus, now everyone with access to this repository knows your access token.

Instead, NavigationController’s initializer should accept an access token as an optional argument. In the example application, use a placeholder token, which looks like this inside Xcode:

If the developer doesn’t specify an access token, NavigationController can create Directions with a nil access token, which will cause Directions to automatically look in the Info.plist.

/cc @bsudekum

[bsudekum]

@1ec5 as it stands, the developer is required to make all routing requests. 892f1e5 is in the example app, are you thinking that direction routing logic should be moved to this lib?

[1ec5]

No, I was merely stating that your access token shouldn’t live anywhere in this repository, in case we make the repository public. The suggestion above is one way to accomplish that, but this document outlines another approach that might be more convenient for you (and less discoverable to anyone checking out this repository).

[bsudekum]

Fixed with ae0cf54