prep for CRAN initial release

[timelyportfolio]

leaflet.extras would be even awesomeR if on CRAN. If possible, I would love to see it hit CRAN before useR 2017, which would also mean mapedit could release prior to useR. I will volunteer to do the early prep work and track at forked branch.

checklist from CRAN check

• [x] reduce size < 5mb treemap sunburst
  • rbuildignore virginia.rds - delete? https://github.com/timelyportfolio/leaflet.extras/commit/4a41a625dca917ef1bf2c3928fc9200531ed40a1
  • delete mapshaper.js and turf.js since I see no dependencies on these https://github.com/timelyportfolio/leaflet.extras/commit/25d706e9b17f201316c30d9bc329145d2e52da8b
• [x] undocumented arguments https://github.com/timelyportfolio/leaflet.extras/commit/11762c775ffb0a441d327bad1058c781e01983b9

cc @tim-salabim

[timelyportfolio]

After completing the checklist above, passes local CRAN check and rhub::check_for_cran().

[bhaskarvk]

Working on this now, will submit to CRAN before EOD. Thanks so much for taking a lead on this.

[bhaskarvk]

Submitted to CRAN. Fingers crossed!