Decrement the gem upgrade cost as upgrade progresses

[TboneX]

I just noticed this and thought that it would be a nice improvement that would help out both players and BB.

When a building is upgrading, the gem cost for the upgrade does not count down as the time remaining decreases.

That should be changed so that the gem cost decreases proportionate to the time remaining. (If an upgrade costs 25,000 gems and a player has 20,000 but can't or won't buy more, then the player currently winds up keeping those 20,000 gems to spend (or not) at a later time. Even if the player comes into gems later during that same upgrade process, they may not wish to spend them to remove a now-shorter waiting period. Removing a 7 day timer may be worth 25,000 gems, but it's certainly not worth that price to remove a 6 hour timer. This hurts the player who could get a benefit from the gems if they could be spent more flexibly on such upgrades and hurts BB because players who don't spend (and buy) gems aren't contributing financially to the operation of the game.)

Opening up more flexibility here will make the purchase of gems a more likely occurrence as the options for spending increase.

[Perwyn]

Great idea! The only place I know of where the gem price decrements is the barracks. It would be handy to apply this to anything that can instant finish with gems. I may not ever pay 200 to instant finish a tome for example, but am likely to pay 50 to instant finish one 3/4 done right before bedtime so I can queue up something else.