Reset geom defaults after using the theme

[maartenzam]

Currently, some default settings for some geoms are changed when theme_wb() is added to a plot, see

wbplot/R/theme_wb.R

Line 58 in 8a3bd96

# Change default geom aesthetics

Ideally, this should be reverted when a plot is generated without theme_wb(), and when the wbplot package is detached from the session. The last paragraph under "Maintaining ggplot2" in this blog post, suggests that default aesthetic settings will be added to themes in coming versions of ggplot2. But for now, a manual cleanup function to restore the defaults is probably the best solution.