Error(s) in re-building vignettes:
--- re-building ‘conversions.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 49-55 (conversions.Rmd) 
Error: processing vignette 'conversions.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘conversions.Rmd’

--- re-building ‘customize_plot.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 78-81 (customize_plot.Rmd) 
Error: processing vignette 'customize_plot.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘customize_plot.Rmd’

--- re-building ‘incidence_class.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 47-50 (incidence_class.Rmd) 
Error: processing vignette 'incidence_class.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘incidence_class.Rmd’

--- re-building ‘incidence_fit_class.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 55-63 (incidence_fit_class.Rmd) 
Error: processing vignette 'incidence_fit_class.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘incidence_fit_class.Rmd’

--- re-building ‘overview.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 132-135 (overview.Rmd) 
Error: processing vignette 'overview.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘overview.Rmd’

SUMMARY: processing the following files failed:
  ‘conversions.Rmd’ ‘customize_plot.Rmd’ ‘incidence_class.Rmd’
  ‘incidence_fit_class.Rmd’ ‘overview.Rmd’

Error: Vignette re-building failed.
Execution halted