delay evaluation of chunk exec queue if R is executing code

open .nb.html files into untitled buffer if conflicting .Rmd exists

use .nb.html over local cache if newer (e.g. from vcs)

add support for user-specified notebook plot dimensions

add support for user-specified notebook plot dimensions

Merge branch 'master' of github.com:rstudio/rstudio

clean up line widget DOM elements more thoroughly

clean/hide chunk output block when no output is produced

unfold chunks to reveal execution status in notebook

avoid range filtering on extremely large numeric values (unsupported)