rsmatrix 0.2.9

• Updated maintainer email.

• rs_pairs() gets a new argument match_first to control if products in the
  first period match to themselves (#1).

rsmatrix 0.2.8

• Added a vignette.

• rs_matrix() is about twice as fast now.

rsmatrix 0.2.6

• Updated to work with Matrix >= 1.5-0.