Research breakthroughs

**What do you want to see?**
A game setup option to give all techs a chance for a random breakthrough based on percentage completed - can be set to disabled, square, linear, or square root, in increasing order of likelihood.

**How would it help players?**
Encourage players to actually research multiple techs simultaneously.

**Alternatives**
N/A

**Screenshots and mockups**
N/A

**Things to consider**
N/A