Don't interrupt entity follow when using a spidertron remote

[Gorfiend7]

TL;DR

Be able to stay centered on a spidertron while giving new commands to it with a remote.

What ?

When following an entity (either the "Open this location in the map" for trains, or a script that calls open_map with an entity), using a remote (spidertron or artillery) will cause you to stop following that entity. It's currently possible to use other items like blueprints/deconstruction planner while continuing to follow the entity - it should also be possible to use a spidertron remote (and possibly also any other kind of remote).

Why ?

Specifically, it would be useful to be able to give remote commands to a spidertron you are currently following. This can make it easier for a player that is using remote spidertrons for building/combat, by reducing the need to manually move the map.