Adding BggCollection and BggCollectionItem.
Adding BggSearch and BggSearchResult.
Allow a BggCollectionItem to fetch the BggGame associated with it.
Cleaning up unnecessary BggApi calls. The OO interface should be used instead.

Also removing the unnecessary sample_data files that are no longer being used.
Cleaning up the BggGame spec and adding/renaming a few fields.
Adding a way to fetch plays, making it smart enough to deal with the paging.