Need to be able to select two related fields in a single dictionary

[matthewfranglen]

The selection of indexes should allow for selection of multiple different indexes at a given level. This is useful because sometimes there are large dictionaries of details where only a few fields are of interest.

For example, in the sessionstore.js file created by firefox there is a dictionary per open tab. Each open tab has a large number of keys, but usually only the title and url are of interest. It is currently impossible to select both title and url with a single query without getting the excess keys.