#94 revert away from bounding box query to old simple query

Sorry @remigr, I had to revert this for now. There seems to be a
problem I couldn’t track (and didn’t notice at first).

All works otherwise perfect, but it doesn’t show right offers for
markers and I couldn’t find a pattern. Usually at first click I’d see
correct result but with next clicks I’d see what I chose earlier.

So, we’re obviously in need of better test data to catch these.