Imported GNU-R version 66465 from http://svn.r-project.org/R/trunk
DispatchGroup optimization (extracting loop invariant expression). Cleanups - extracting methods.
One more DispatchGroup optimization - extracting updating via S4 slot to a method, avoiding some branches.
Remove unused variables.
Indentation fix.
Introduced installChar (faster than install(CHAR)).
Merge branch 'install-char-optimizations2' of http://www.github.com/kalibera/rexp into install-char-optimizations2