dillon1000/react

Enable hook syntax support

Updates the compiler to understand Flow hook syntax. Like component syntax, in 
infer mode hooks are compiled by default unless opted out. 

Looking ahead, i can imagine splitting up our compilation modes as follows: 

* Annotations: opt-in explicitly 

* Declarations: annotations + component/hook declarations 

* Infer: annotations, component/hook declarations, + component/hook-like 
functions 

This also suggest an alternative annotation strategy: "use react" (or "use 
component" / "use hook") as a general way to tell the compiler that a function 
is intended for React. Then opting out of memoization could do "use 
react(nomemo)".