CRAN release for v0.5?

[cpsievert]

Both shiny and plotly have invested interested in seeing a DT release to CRAN. Do you have a schedule in mind for that?

Also, it looks like the plotly related feature I added in #498 didn't make it into to NEWS, so perhaps we could add this bullet?

* DT can now respond to plotly's persistent selection mode (thanks, @cpsievert, #498)

[yihui]

as if you were standing in my back... I'm just doing this right now.

[yihui]

On CRAN now.