check for null before invoking file system context callbacks
Merge branch 'master' of github.com:rstudio/rstudio
use @concept rather than @concepts for roxygen2

see: https://github.com/klutometis/roxygen/issues/268
eliminate overwrite check in viewer export

this was causing many undesirable interactions including re-setting of the iframe to size 0,0
Merge pull request #155 from rstudio/bugfix/viewer-export-overwrite

eliminate overwrite check in viewer export
pin embedded versions of packrat and rmarkdown
handle null or empty source file attributes gracefully
Unload namespace if necessary after .rs.getPackageRStudioProtocol; internal logic for packify
Merge pull request #159 from rstudio/bugfix/ensure-packrat-unloaded-if-unused

Unload packrat after calling it to check project context
Merge pull request #158 from rstudio/bugfix/empty-debug-path

Handle null or empty source file attributes gracefully
update to pandoc 1.12.4.2
don't scan for .libPaths() changes while debugging
don't Step Into functions run by RStudio itself
protect additional vulnerable executions with DisableStepInto
don't restore browser command after debugging ends
bind to revealjs size on suffix
embed mathjax 2.3
use RDEBUG flag on global environment instead of R_BrowserLastCommand
save/restore debug flag on non-global environments
Merge pull request #163 from rstudio/bugfix/toplevel-stepinto

Fix runaway recursion resulting from Step Into