shiny issues (not critical for tmap4 release)

[mtennekes]

There are still a couple of shiny issues:

1. renderTmap had mode-specific functions (not S3 but sort of): https://github.com/r-tmap/tmap/blob/master/R/tmapLeafletShiny.R However, I tried calling these functions with do.call https://github.com/r-tmap/tmap/blob/master/R/shiny.R#L46-L47 but that didn't work. For now, I hard-coded the mode-specific approached in these functions, with an error for modes other than plot and view.

2. Probably my lack of shiny knowledge. In view mode, tmapProxy is already triggered at start up. So after the initial map rendering, the map is immediately updated, which takes a bit of time. See code in this vignette https://r-tmap.github.io/tmap/articles/adv_shiny#view-mode

3. In the same code example, the tmapProxy doesn't work when the original (projected) sf objects are used.

The examples in the documentation and the vignette work, so these issues are not critical for the upcoming tmap4 release.