Merge pull request #206 from romainfrancois/master

Better Rcpp::stop
catch-up entry for Romain's PR
new config macro to also account for dev version, ie 'd' in a.b.c.d
bumped desription
more compact expression
use of \code{} in NEWS and minor rewording
Merge pull request #207 from RcppCore/feature/four-part-version-macro

Feature/four part version macro
undo some Romain-isms (#207)
additional protection via Shield<SEXP> for tail objects, as suggested by Martin Morgan
Merge pull request #208 from RcppCore/feature/protect-grow

additional protection via Shield<SEXP> for tail objects, as suggested by...