Fixed TopicSourceUrl wrappers so that they are updateable.
Reworked the database provider so that collection wrappers reference the actual object collection and not a copy.
Re-added missing File and LanguageFile Wrappers and Providers
Fixed a bug where the providers weren't returning an updateable collection for topic source urls.
Added Wrapper caching so that if the same objects are passed then a cached wrapper will be used. Fixed a bug where using lists would cause data to be lost.