clean up error and event handling in R Markdown template discovery
clean up dialog UI and progress display for New R Markdown dialog
check for template output target existence more robustly
restore border when no templates are found
preserve selection after run previous chunks
don't do error navigation when previewing source-only
ensure html preview is wide enough to exceed bootstrap responsive threshold
change devtools default
Revert "change devtools default"

This reverts commit 7d74516d496b301e95f3c09208f8c322d735ea86.
Merge remote-tracking branch: upstream/master