obvious fix for #209. not so obvious to deal with the consequences
fixed const correctness of Vector::const_iterator. closes #209
added ChangeLog entry for Romain's PR211
bump (dev-)Version and Date
minor edit on NEWS entry
fix const correctness of Matrix::Column( const Matrix&, int)
manual merge
Merge pull request #216 from RcppCore/feature/pr211+pr212-const-iterator

Feature/pr211+pr212 const iterator