API naming conflict across different route prefixes

[kdeininger]

Creating two APIs with the same name but different route prefixes should be possible. But this doesn't work because only the name is written to the registry:
https://github.com/vvmruder/pyramid_georest/blob/master/pyramid_georest/lib/rest.py#L846-L855

Suggested fix:
Write the combination of config.route_prefix and the API name to the registry. For example:

reg_name = urlparse.urljoin(config.route_prefix, name)
if reg_name not in config.registry.pyramid_georest_apis:
    config.registry.pyramid_georest_apis[reg_name] = self
    config.commit()
    create_api_routing(config, self)
else:
    log.error(
        "The Api-Object you created seems to already exist in the registry. It has to be unique at all. "
        "Couldn't be added. Sorry..."
    )
    raise LookupError()