Several learning rate schedulers were added to the modeling functions (#12).

An

`optimizer`

was added to [brulee_mlp()], with a new default being LBFGS instead of stochastic gradient descent.

Modeling functions gained a

`mixture`

argument for the proportion of L1 penalty that is used. (#50)Penalization was not occurring when quasi-Newton optimization was chosen. (#50)

First CRAN release.