Fleet repair ships should come sooner/Repair should function like Sentry

Maybe not as big an issue on smaller maps, but if you're playing on Large or above, it can be a significant pain to keep popping over to check each and every single fleet every turn to make sure it's not about to be ambushed when put on Repair.  Repair should thus work similarly to Sentry, waking the fleet up automatically when enemy gets near. 

Also seems like fleet repair options should come sooner in tech tree, but maybe I'm just not beelining to the right tech fast enough.