Error(s) in re-building vignettes:
--- re-building ‘demo.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
Loading required package: beautier
Loading required package: beastier
Loading required package: mauricer
Loading required package: tracerer
--- finished re-building ‘demo.Rmd’

--- re-building ‘examples.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
Loading required package: beautier
Loading required package: beastier
Loading required package: mauricer
Loading required package: tracerer
--- finished re-building ‘examples.Rmd’

--- re-building ‘nested_sampling.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
--- finished re-building ‘nested_sampling.Rmd’

--- re-building ‘step_by_step.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
Loading required package: beautier
Loading required package: beastier
Loading required package: mauricer
Loading required package: tracerer
Quitting from lines 44-51 (step_by_step.Rmd) 
Error: processing vignette 'step_by_step.Rmd' failed with diagnostics:
Cannot write to file with name '/Users/urbanek/Library/Caches/beast2_1509e75653aa.xml' 
Perhaps no permission to write there? 
Error message: cannot open the connection 

--- failed re-building ‘step_by_step.Rmd’

--- re-building ‘tutorial.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
--- finished re-building ‘tutorial.Rmd’

SUMMARY: processing the following file failed:
  ‘step_by_step.Rmd’

Error: Vignette re-building failed.
Execution halted