extend query track(s) when genes "just outside" neighborhood belong to families of genes within neighborhood(s)

[adf-ncgr]

Currently, there's a bit of asymmetry in terms of the way that query and result tracks behave with respect to their bounds. A result track extent is "greedy" in the sense that it will be extended to include genes belonging to families considered matchable, while query track(s) have fixed boundaries based on the neighborhood parameter. This can lead to some potentially misleading results, suggestive of copy number variation on the edges of tracks (as in an example which I thought I had open in one of many browser tabs, but it's not coming to hand- will update this issue if I find it or an equivalent example later). It seems as though the new architecture might facilitate this since the query tracks should be easily extendable without needing to make this a server-side decision?