use of unexported functions (:::) from mapview

[timelyportfolio]

@tim-salabim don't think CRAN is going to let us get away with using unexported functions from mapview any more. I'm not sure how we got away with it in earlier versions. How should we handle?

https://github.com/r-spatial/mapedit/blob/master/R/edit.R#L242
https://github.com/r-spatial/mapedit/blob/master/R/edit.R#L250

https://github.com/r-spatial/mapedit/blob/master/R/select.R#L60
https://github.com/r-spatial/mapedit/blob/master/R/select.R#L72

https://github.com/r-spatial/mapedit/blob/master/R/playback.R#L46
https://github.com/r-spatial/mapedit/blob/master/R/playback.R#L55
https://github.com/r-spatial/mapedit/blob/master/R/playback.R#L66