Updated maintainer email.
rs_pairs() gets a new argument match_first to control if products in the
first period match to themselves (#1).
Added a vignette.
rs_matrix() is about twice as fast now.
Making the "Y" vector with rs_matrix() no longer gives an error with
length-0 inputs and a factor with non-empty levels.
rs_matrix() cleans up the enclosing environment of its result.
rs_pairs() and rs_matrix() are now faster, and less picky about their
inputs for time periods.rs_pairs() has been reworked to be much faster and more general,
while rs_unpair() has been removed. These changes are not backwards compatible.
Added French translations.
Fixed the NOTE about LazyData from CRAN.