Not really sure how to pull or merge for a feature enhancement. In the Calendar module, I noticed that when "dateheaders" is selected, "showEnd" doesn't do anything but it would be reasonable to allow the option to show an end time, especially since showEnd is false by default.

From line 273 in calendar.js, I added an if statement to check for showEnd and publish the end time of an event:
timeWrapper.innerHTML = moment(event.startDate, "x").format("LT");
//Add for End Date from showEnd for dataheaders
if (this.config.showEnd) {
timeWrapper.innerHTML += " - " + moment(event.endDate, "x").format("LT");
}

Not sure if this is helpful but I figured I would put it out there.