Pass endPoint as second argument of onSelectionChange

[orangecoloured]

Having the endPoint as second argument of onSelectionChange could help with some UX stuff, like popping up some actions panel for highlighted elements in that point. Atm an additional listener is required to accomplish this.

[aurbano]

@orangecoloured makes sense, I'm a bit busy these days but feel free to send a PR with the change if you want! :)

[orangecoloured]

#48