Space Elevator Phase Nodes

In modeller all Space Elevator Phase node make the ridiculous assumption that each phase will be completed in a single minute.

Absolutely no one plans for this.

Add a completion time setting to these nodes.

If you for instance set this to 10 minutes, what would have been a totally impossible demand of 1,162 Iron Ore per minute for phase 1 becomes a perfectly acceptable demand of 116 Iron Ore per minute.

Its a simple change requiring minimal calculations and would make using the modeller so much easier