6.0.0

• Calling .then on a custom promise that inherits from Promise will return an instance of the custom promise type. This simplifies writing custom promise implementations on top of Promise
• Remove an internal call to Object.create (making it easier to polyfil older browsers)
• Pass through this context in .nodeify
• Split extensions into separate files
• REMOVE Promise.from
• REMOVE Promise.cast
• REMOVE support for multiple arguments to Promise.all (i.e. you must do Promise.all([a, b]) instead of Promise.all(a, b))
• REMOVE node specific extensions from browser polyfill (i.e. nodeify and denodeify). These remain in the CommonJS version.