Properly evaluate instance properties

[kaidesu]

Properly evaluates class instance properties. You can now assign properties directly within the constructor:

class Circle {
  function constructor(area = 5) {
    this.area = area
  }

  function area() {
    return math.pi * this.area * this.area
  }
}

circle = Circle.new(10)

print(circle.area())

// 314.1592653589793

Closes #119

[skx]

This probably doesn't need to remain here..

[kaidesu]

Thanks for catching this! This has been cleaned up.