fix bug: package breakpoints set after library() sometimes miss srcrefs
don't do install.packages checks for repos = NULL
pandoc binaries for redhat/fedora
Revert "pandoc binaries for redhat/fedora"

This reverts commit 9da6fd349aad50f8cbe59d8ef3fec8897d9a8898.
use custom pandoc binaries for redhat5
provide default for repos option
Merge branch 'master' of github.com:/rstudio/rstudio
Merge remote-tracking branch: upstream/master