add incoming check for some checks...

git-svn-id: https://svn.r-project.org/R/trunk@63831 00db46b3-68df-0310-9c12-caf00c1e9a41
New argument keep.null=FALSE for modifyList()

git-svn-id: https://svn.r-project.org/R/trunk@63832 00db46b3-68df-0310-9c12-caf00c1e9a41
allow Bioc version to be overridden

git-svn-id: https://svn.r-project.org/R/trunk@63833 00db46b3-68df-0310-9c12-caf00c1e9a41
A little more explanation of how breakpoints are chosen.

git-svn-id: https://svn.r-project.org/R/trunk@63835 00db46b3-68df-0310-9c12-caf00c1e9a41
Warn about inst/build in package sources.

git-svn-id: https://svn.r-project.org/R/trunk@63837 00db46b3-68df-0310-9c12-caf00c1e9a41
Remove support for .install_timestamp mechanism.

git-svn-id: https://svn.r-project.org/R/trunk@63841 00db46b3-68df-0310-9c12-caf00c1e9a41
remove upquote.sty as readily available now

git-svn-id: https://svn.r-project.org/R/trunk@63845 00db46b3-68df-0310-9c12-caf00c1e9a41
back out r63845

git-svn-id: https://svn.r-project.org/R/trunk@63849 00db46b3-68df-0310-9c12-caf00c1e9a41
Spell checking packages uses a top-level .aspell directory.

git-svn-id: https://svn.r-project.org/R/trunk@63850 00db46b3-68df-0310-9c12-caf00c1e9a41