Error(s) in re-building vignettes:
--- re-building ‘ConditionalErrorSpending.Rmd’ using rmarkdown

Quitting from lines 54-58 [unnamed-chunk-2] (ConditionalErrorSpending.Rmd)
Error: processing vignette 'ConditionalErrorSpending.Rmd' failed with diagnostics:
there is no package called 'systemfonts'
--- failed re-building ‘ConditionalErrorSpending.Rmd’

--- re-building ‘ConditionalPowerPlot.Rmd’ using rmarkdown

Quitting from lines 30-34 [unnamed-chunk-2] (ConditionalPowerPlot.Rmd)
Error: processing vignette 'ConditionalPowerPlot.Rmd' failed with diagnostics:
there is no package called 'systemfonts'
--- failed re-building ‘ConditionalPowerPlot.Rmd’

--- re-building ‘GentleIntroductionToGSD.Rmd’ using rmarkdown

Quitting from lines 166-167 [unnamed-chunk-2] (GentleIntroductionToGSD.Rmd)
Error: processing vignette 'GentleIntroductionToGSD.Rmd' failed with diagnostics:
there is no package called 'systemfonts'
--- failed re-building ‘GentleIntroductionToGSD.Rmd’

--- re-building ‘GraphicalMultiplicity.Rmd’ using rmarkdown
--- finished re-building ‘GraphicalMultiplicity.Rmd’

--- re-building ‘PoissonMixtureModel.Rmd’ using rmarkdown

Quitting from lines 26-31 [unnamed-chunk-2] (PoissonMixtureModel.Rmd)
Error: processing vignette 'PoissonMixtureModel.Rmd' failed with diagnostics:
there is no package called 'systemfonts'
--- failed re-building ‘PoissonMixtureModel.Rmd’

--- re-building ‘SpendingFunctionOverview.Rmd’ using rmarkdown
--- finished re-building ‘SpendingFunctionOverview.Rmd’

--- re-building ‘SurvivalOverview.Rmd’ using rmarkdown

Quitting from lines 30-34 [unnamed-chunk-2] (SurvivalOverview.Rmd)
Error: processing vignette 'SurvivalOverview.Rmd' failed with diagnostics:
there is no package called 'systemfonts'
--- failed re-building ‘SurvivalOverview.Rmd’

--- re-building ‘VaccineEfficacy.Rmd’ using rmarkdown

Quitting from lines 28-31 [unnamed-chunk-2] (VaccineEfficacy.Rmd)
Error: processing vignette 'VaccineEfficacy.Rmd' failed with diagnostics:
there is no package called 'systemfonts'
--- failed re-building ‘VaccineEfficacy.Rmd’

--- re-building ‘binomialSPRTExample.Rmd’ using rmarkdown

Quitting from lines 47-48 [unnamed-chunk-2] (binomialSPRTExample.Rmd)
Error: processing vignette 'binomialSPRTExample.Rmd' failed with diagnostics:
there is no package called 'systemfonts'
--- failed re-building ‘binomialSPRTExample.Rmd’

--- re-building ‘gsDesignPackageOverview.Rmd’ using rmarkdown

Quitting from lines 65-70 [unnamed-chunk-2] (gsDesignPackageOverview.Rmd)
Error: processing vignette 'gsDesignPackageOverview.Rmd' failed with diagnostics:
there is no package called 'systemfonts'
--- failed re-building ‘gsDesignPackageOverview.Rmd’

--- re-building ‘gsSurvBasicExamples.Rmd’ using rmarkdown

Quitting from lines 47-60 [unnamed-chunk-2] (gsSurvBasicExamples.Rmd)
Error: processing vignette 'gsSurvBasicExamples.Rmd' failed with diagnostics:
there is no package called 'systemfonts'
--- failed re-building ‘gsSurvBasicExamples.Rmd’

--- re-building ‘hGraph.Rmd’ using rmarkdown
--- finished re-building ‘hGraph.Rmd’

--- re-building ‘nNormal.Rmd’ using rmarkdown

Quitting from lines 28-31 [unnamed-chunk-2] (nNormal.Rmd)
Error: processing vignette 'nNormal.Rmd' failed with diagnostics:
there is no package called 'systemfonts'
--- failed re-building ‘nNormal.Rmd’

--- re-building ‘toInteger.Rmd’ using rmarkdown
--- finished re-building ‘toInteger.Rmd’

SUMMARY: processing the following files failed:
  ‘ConditionalErrorSpending.Rmd’ ‘ConditionalPowerPlot.Rmd’
  ‘GentleIntroductionToGSD.Rmd’ ‘PoissonMixtureModel.Rmd’
  ‘SurvivalOverview.Rmd’ ‘VaccineEfficacy.Rmd’
  ‘binomialSPRTExample.Rmd’ ‘gsDesignPackageOverview.Rmd’
  ‘gsSurvBasicExamples.Rmd’ ‘nNormal.Rmd’

Error: Vignette re-building failed.
Execution halted