Bind methods to scope

[Fry98]

Methods inside a scope aren't bound to it which causes issues when they're used as a callback (e.g. for setInterval, window events, etc.).

Example: https://codesandbox.io/embed/nice-sun-71j3r
(this.count should get incremented on keydown but it doesn't because this inside the inc() methods points to Window instead of the scope)