feat(dom): overload .event() method using HTMLElementEventMap (#682)
feat(dom): overload .event() method using HTMLElementEventMap (#682)

The lib.dom.d.ts file contains a mapping where the name of the event type is mapped to the event
type itself (e.g. click -> MouseEvent). Using this mapping on the DOMSource.events() function allows
the correct event stream to be returned.
cyclejs/cycle-core,usm4n/cyclejs,usm4n/cyclejs,cyclejs/cycle-core,ntilwalli/cyclejs,cyclejs/cyclejs,cyclejs/cyclejs,usm4n/cyclejs,cyclejs/cyclejs,staltz/cycle,cyclejs/cyclejs,staltz/cycle,ntilwalli/cyclejs,ntilwalli/cyclejs,ntilwalli/cyclejs,usm4n/cyclejs