forward_sel: Fit forward stepwise selection survival model Get the cost...
In csetraynor/predsurv: Build and compare diverse prediction survival models.

Fit forward stepwise selection survival model Get the cost and coefficients for forward search survival analysis.

1 2	forward_sel(d_train, g, x_vars, time_var = "time", status_var = "status", penalty = "AIC", save_file)

`d_train`	dataframe
`g`	additional data frame for bootstrapping
`x_vars`	vars to analysis
`time_var`	defults to time
`status_var`	defaults to status
`penalty`	information criteria to use: AIC or BIC
`save_file`	should results be saved on file
`ncores`	for parallel.