Allow pausing of an upgrading building to free up a builder to upgrade walls
I'm working hard gathering resources and i get up to max storage. I have 3 builders all busily working away on some upgrade. I would like the ability to pause one of my buildings (which would cause that building to stop upgrading but still not function.) This would allow me to spend my resources on walls before some random awesome guy steals them.
Since the building that is paused would still not function this would not be very overpowered or unbalanced and also allow for another fun aspect of the game... do I pause this or let it finish? more decisions.