Select feature in JOSM/ID when geometry is a GeometryCollection

Not sure if the selecting of features works at all (#77, #161), but it definitely doesn't work when the geometry type is a GeometryCollection (as in my case). Reason is that this case is missing in the switch at https://github.com/maproulette/maproulette2/blob/master/app/assets/javascripts/mapping.js#L1167-L1180 and https://github.com/maproulette/maproulette2/blob/master/app/assets/javascripts/mapping.js#L1117-L1130.

Also I would suggest to optionally allow something like node_id, way_id, and relation_id instead of or in addition to osmid, to allow setting this more explicitly. Only because the geometry shown is, say a Point, it doesn't mean it must have been created from a node (could be the center of an area, or the point of the only node in a single-node way we are trying to repair for instance.)

Start with the selection logic in app/assets/javascripts/mapping.js at the switch blocks around lines 1117-1130 and 1167-1180, then compare how Point, way, and relation geometries are handled. Reproduce selection with a GeometryCollection and verify the requested JOSM/iD behavior; treat the node_id, way_id, and relation_id proposal as a separate scope decision.