Trigger "repositioned" event after position change

[TrevorBurnham]

Fixes #195.

@slorber Try this out locally and see if it works for you, OK?

[slorber]

Hey, thanks it works great for my usecase you can release that :)

I use react-tether and had to hack a bit the library so that it supports something like:

      <TetherComponent
        attachment={this.props.hotspotPosition}
        targetAttachment={this.props.hotspotPosition}
        className={"onboarding-hotspot-tethered " + this.props.name}
        offset={this.props.hotspotOffset}
        constraints={[{
          to: 'scrollParent',
          attachment: 'none'
        }]}
        on={[
          {
            event: "repositioned",
            fn: this.repositionTooltip
          }
        ]}
      >

By the way, I think it would be useful to document that event system because I couldn't find anything in doc about it.

Also, would find it useful to have events for entering/leaving out-of-bound/pinned state as it would permit to avoid querying class names on tether dom node

[TrevorBurnham]

Also, would find it useful to have events for entering/leaving out-of-bound/pinned state

You should be able to do that by responding to the "update" event, which fires whenever the Tether's attachment is overridden by a constraint.

[slorber]

Ok thanks :)