Reduction of the number of constructors

[kyomawolf]

How about doing this for the Vector2, 3, 4 classes as well?

[RobLoach]

yeah If we do take this approach, I'd like to do a few things...

• Add more tests to make sure the constructors still work properly
• Apply the same pattern across the rest of the data types

I do remember running into an issue with the initializer list understanding the default parameters, but I'm not sure where/when it happened.