Log Message:
(graphics/R-ggExtra) Updated 0.8 to 0.9

# ggExtra 0.9

- Fix #109: using ggMarginal on a plot where geom_point was not the first layer \ 
was buggy (#116)
- Add documentation about how to use ggMarginal in R Notebooks or Rmarkdown
- Added support for densigram (density+histogram) plots (#118)
- Lots of internal refactoring (thanks @crew102)
- Fix the "two chunk" requirement for rendering ggMarginalPlots in Rmd \ 
(#148)