Command line tool should accept multiple configurations

[1ec5]

The command line tool should accept multiple configuration files or a configuration file plus a URL, merging the various options into a single request. It currently accepts only one configuration file or a URL, which makes it awkward to describe what the argument should be.

/ref #728 (comment)
/cc @mapbox/navigation-ios

[jill-cardamon]

Closing this ticket since this might not be an improvement. While this addition would bring clarity to the option description and make it possible for the user to pass multiple paths/URLs or specify the same option multiple times, the behavior might be unexpected and unclear to users (will the tool send multiple requests? when will it fail?).