gbm3: generalized boosted models ----0------------------------

Originally written by Greg Ridgeway, added to by various authors, currently maintained by Harry Southworth. Development is discussed --- somewhat --- at https://groups.google.com/forum/#!forum/gbm-dev .

This is the shiny new gbm3 package that is not backwards compatible, but is fast and parallel and --- to some extent --- developed.

Non-production releases (bug fixes, mostly) will be released via the GitHub release workflow. To install from GitHub, first install devtools from CRAN:

install.packages("devtools")

Then install gbm3 from GitHub:

library("devtools")
install_github("gbm-developers/gbm3")