Birthdays / Current Week not rendered if no events or get_events

[bcongdon]

If the ReactLifeTimeline component is created without a non-zero length events prop or without a get_events, then birthday / current_week events are never rendered.

Looks like this section should be changed to something like:

if (this.props.get_events != null && this.props.events.length == 0) this.props.get_events(this.got_events.bind(this));
else this.got_events(this.props.events);