Production conversions should always be at the bottom of the queue

Raise your hand if you've run into the following situation:

1. Many of your systems have already built all the system improvements they can, so you queue up the production conversions (Public 3D Printing or Planet Cracker Factory/Lab).
2. Sometime later, you research a tech unlocking a new system improvement.
3. You now have to go thru each and every system not only queueing up the new system improvement, but also rearranging the build order so your new system improvement isn't forever stuck in limbo behind the inifinite improvement.

My suggestion is that infinite system improvements always be at the bottom of the production queue; there's no reason the player would ever actually want a finite turn system improvement queued behind an infinite one, and it would save a lot of micromanagment hassle if the newly added system improvement jumped ahead of the infinite one. There is an issue of what to do if the player tries queueing multiple infinite improvements, but again, I can't think of a reason why a player would do this; if necessary, I would suggest greying out all other inifinite system improvements once one is in the queue.