Implement lexic scope

[jespa007]

like javascript does, local function inside functions captures all local variables and it stores in a "environment" as extern scope,

Example,

function f1(){
  var i=0;

  return function(){
        i++;
        Console::outln(i)
  }

}

var f=f1();
f(); // <-- it prints 1
f();// <-- it prints 2

So if the variable is not found as local, then it tries to find it in its environment.