The Usability Language Static Analysis

There are a handful of usability language features that we added to make the static analysis tolerable. A, so we do definite assignment analysis for local variables where it works and that gives you the flexibility to defer initialization. But it doesn't work for fields and top lobl variables. So for those, we added a late modifier. The basically says, do that initial check at run timek. And what that lets you do is make a a non nullable variable that you initialize later.