v0.4.0

Breaking changes

• Change Bind implementation to use flatMap instead of flatMapLatest
• Change scan param order
• Use require for loading Rx (this means you'll need to use browserify in
  order to deploy to the browser)

New features

• Add distinct, distinctUntilChanged, filter (@pelotom)
• Add generate and range
• Add withLatestFrom
• Add runObservable