Fix snowballing by socializing kill gold

I think this is the main reason games snowball so hard now, and something that prevents bounty gold from facilitating comebacks unless the game is relatively even.

Someone on the enemy team is fed to shit. You bust your ass to take down this fed monstrosity, blowing all of your summoner spells and cooldowns, but they just barely escape you. Your team mate catches them and secures the kill. You get an entire 150g for your effort, while the team mate who got the killing blow receives 1000g. This makes no sense.

There are also often games where both teams are close in terms of kills and gold, but one team has all of their kills consolidated into the ADC. The ADC with all the kills basically just steamrolls the other team, because they have such a massive gold advantage.

This is also applicable when playing champions who don't scale well into the late game. When I'm playing Udyr, I have to intentionally try not to get killing blows, because my champion doesn't translate well into the late game. This isn't healthy.