Cached queries ignore Query output branch selections

[gkunter]

The SQL query string doesn't know whether anything in the Query output branch is selected (e.g. Query String). But as this string is used as a key when accessing cached queries (which, in turn, include the data from the Query output branch), queries will always return the same cached data frame, regardless of what is selected in the Query output branch.

Solution: also use the selected features as the key to the query cache?

[gkunter]

Can't reproduce. Test case: Buckeye corpus, query string * christmas *, with Word as only selected resource. Querying with Query string selected returns from the cache a data frame with three word columns and the query string column. Without Query string, the retrieved data frame doesn't contain a query string column.