Add ItemSelected event and command

[Wenfengcheng]

Hi Suave,

I have made a pull request #3 to add itemselected event, please check it and merge to the branch.

Thanks,
Wenfeng

[Wenfengcheng]

Hi @SuavePirate ,

I also mentioned this to you in another project DynamicWrapLayout. Maybe I can also add this feature to that project.

Thanks,
Wenfeng