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

Attaching package: 'dplyr'

The following objects are masked from 'package:stats':

    filter, lag

The following objects are masked from 'package:base':

    intersect, setdiff, setequal, union


Attaching package: 'lubridate'

The following object is masked from 'package:base':

    date


Attaching package: 'zoo'

The following objects are masked from 'package:base':

    as.Date, as.Date.numeric

Warning in bind_rows_(x, .id) :
  Unequal factor levels: coercing to character
Warning in bind_rows_(x, .id) :
  binding character and factor vector, coercing into character vector
Warning in bind_rows_(x, .id) :
  binding character and factor vector, coercing into character vector
Warning: Removed 5 rows containing missing values (geom_path).
Don't know how to automatically pick scale for object of type difftime. Defaulting to continuous.
Don't know how to automatically pick scale for object of type difftime. Defaulting to continuous.
Don't know how to automatically pick scale for object of type difftime. Defaulting to continuous.
--- finished re-building ‘osem-history.Rmd’

--- re-building ‘osem-intro.Rmd’ using rmarkdown
Loading required package: maps
Loading required package: maptools
Loading required package: sp
Checking rgeos availability: TRUE
Loading required package: rgeos
rgeos version: 0.4-2, (SVN revision 581)
 GEOS runtime version: 3.6.1-CAPI-1.10.1 
 Linking to sp version: 1.3-1 
 Polygon checking: TRUE 

Quitting from lines 85-90 (osem-intro.Rmd) 
Error: processing vignette 'osem-intro.Rmd' failed with diagnostics:
parse error: premature EOF
                                       [{"_id":"5710de1a45fd40c8198cce
                     (right here) ------^

--- failed re-building ‘osem-intro.Rmd’

--- re-building ‘osem-serialization.Rmd’ using rmarkdown
Quitting from lines 41-48 (osem-serialization.Rmd) 
Error: processing vignette 'osem-serialization.Rmd' failed with diagnostics:
502
--- failed re-building ‘osem-serialization.Rmd’

SUMMARY: processing the following files failed:
  ‘osem-intro.Rmd’ ‘osem-serialization.Rmd’

Error: Vignette re-building failed.
Execution halted