[f2c] Licenses not converted correctly

[Stephen-Gates]

See frictionlessdata/ckanext-datapackager#62

When I upload this datapackage.zip to this ckan site the licenses aren't unpacked correctly

@amercader suggests following algorithm when ingesting DP

• If licenses is present check if the first item exists in the licenses registry.
• If so, set license_id
• If it doesn't exist in the registry, or there is more than one license, store the licenses object as an extra, so instances with the datapackager extension can handle it as they see fit. They will need to take care of keep license_id (the default field) and the licenses extra in sync.

This is good. However, it is only something one can do "inside" CKAN so it is outside of scope here. I would suggest we just convert first license.name in licenses to license_id and license.title to license_title