Add support for national buses and ferries of Nicaragua

[ialokim]

This PR only adds the minimal config.json used by the standard creators. However, to successfully produce the countrywide GTFS, it depends on #114, #124, #125, #126 and (to clean the data up) on #127.

Those PRs should be merged first.

[xamanu]

Yeah, nice progress here! I would like to see #83 going in before also. This list of providers is getting long now.

[ialokim]

I've changed the configuration to allow ferries, too (simply removed route=bus). So now, the ferries from and to Ometepe (e.g. this one) are available inside the resulting GTFS.

[xamanu]

This PR needs to be rebased on the latest commits to the code and modified to stick to the newly introduced naming conventions (see #83 for more information) for selectors.

[ialokim]

This PR needs to be rebased on the latest commits to the code and modified to stick to the newly introduced naming conventions (see #83 for more information) for selectors.

Done. I've renamed the selector to ni_national as suggested in #83.

[xamanu]

Looks good to me! All depending PRs have been accepted. So this is probably ready to be merged.
Cool, that there is now support for ferries!!

[xamanu]

I suggest to include tests for this provider first. Based on the structure of #133 it's quite easy to create them (see #136).

[grote]

@xamanu so you don't want to have this merged until there's tests for it?

[xamanu]

Yes, indeed, In my opinion every (new) creator should now include tests.
This will be a good reference implementation for a new city, based on the standard creators.

[xamanu]

In case #136 gets merged in, I'd be happy to provide the missing tests here. Just waiting for the direction we are taking there.