Possibility for ns collision between module and user defined RDF namespaces

[linclark]

If a namespace is defined in a module, how will we avoid collision with namespaces defined by the user? For instance, if the user defines the 'media' ns as http://digitalbazaar.com/media but a module defines it as the Yahoo vocabulary.

Possible solution: on module install, check to see if it implements hook_rdf_namespaces. If it does, check to see whether the uri of any prefix is different. If so, change the prefix of the mapping in the database and iterate through content type mappings, changing the prefix. DO THIS BEFORE rdf_mappings runs. Print a message to the screen. Allow for this to be cleared manually with a menu callback as well in case an installed module's rdf_namespaces are changed between two versions. Also run on update.