Deck.gl v8.0.0 changes

[SymbolixAU]

Things to watch - visgl/deck.gl#3869

• add deck. to all layers (e.g. deck.ArcLayer({ }) )
• use INITIAL_VIEW_STATE and change how update_view works / change_location
  • md_change_location() no longer works
• layer updates - https://github.com/uber/deck.gl/blob/master/docs/upgrade-guide.md#removed
• resolve bug report
• test this answer - https://stackoverflow.com/questions/57198699/how-to-run-multiple-mapdeck-view-calls-sequentially
• show_view_state still works
• test multiple maps in a single .Rmd document
  • works with v8.0.11, but then the 'INITIAL_VIEW_STATE' fails (whereas IVS works in v8.1.0-alpha.1
• revisit Mapdeck 0.2.1 produces larger files with add_grid #112