constantTimeDispatcher lets you poke a specific react component to do something
without having to do any O(N) operations. This is useful if you have thousands
of RoomTiles in a RoomSubList and want to just tell one of them to update,
without either having to do a full comparison of this.props.list or have each
and every RoomTile subscribe to a generic event from flux or node's eventemitter
*UNTESTED*
Matthew Hodgson