Added compiler support for using new math, subset, and subassign instructions.


git-svn-id: https://svn.r-project.org/R/trunk@66718 00db46b3-68df-0310-9c12-caf00c1e9a41
Enabled use of typed stack.


git-svn-id: https://svn.r-project.org/R/trunk@66719 00db46b3-68df-0310-9c12-caf00c1e9a41
News item for r66718 and r66719.


git-svn-id: https://svn.r-project.org/R/trunk@66720 00db46b3-68df-0310-9c12-caf00c1e9a41