add message reminding the user to send plain text email
Merge pull request #472 from jrnold/release-ascii-email-message

Remind the user to send plain text email
Make insert_global_shims() less chatty
Add dummy namespace
Move infrastructure functions to single file
Upgrade roxygen2
Consistent naming scheme for infrastructure functions
Common method for modifying packages in desc.
Also write better read_dcf and write_dcf
Add use_knitr
Add use_rcpp()
Don't make man/ in create()
Remove --as-cran from project file
updated documentation: roclet names, seealso

... because I often find myself looking up the arguments to roclets, the goal is for `c("collate", "namespace", "rd")` to show up automatically when I type `'document(' -> Tab` in Rstudio.

While here, I also added references to roxygen2 in function description and @seealso
Fix error when help() called and a package has no help files
a vignette engine is of the form pkg::engine_name
Merge pull request #494 from yihui/patch-1

a vignette engine is of the form pkg::engine_name
build_github_devtools: add check for RTools
Update README with info about upgrading devtools
Updated test() doc for updated testthat structure
Rstudio -> RStudio