dillon1000/react

Codegen for early returns in reactive scopes

Implements codegen for reactive scopes with early returns, though we don't ever 
construct such a case yet. See comments in the code. There is a slightly more 
optimal output that would require a larger refactor (also described in code 
comments), for now i'm starting with the simpler approach since this is 
relatively rare so we don't need to optimize code size / runtime as much.