This should make the API functions more accessible for callers as there
won’t be any loose undefined values that were sometimes needed to skip
certain values in certain API endpoints.

Instead, every positional argument is now required and all configurable
options or extensions are part of the options object.

refs #185

API object attribute names are now:

1. camelCased (#164)
2. use Id / Ids suffix for object references (#172)

closes #138