Support adding child to view : Last vs First

[DeathPhoenix22]

Hi,

A little change that helped me a lot, so I though charing it would be good.

Currently when adding a Child to a View (ViewComponent), you're forced to add it "last". I've added the capacity to choose between "last" and "first". By default, nothing was changed, it's added last. You basically can "addFirst" now.

This is extremely useful when you want to attach something under an Entity, but on demand.

Have a nice day.
PR Upcoming.