MultiTaskLasso, GroupLasso and Lasso-like models

[PABannier]

I can certainly implement MultiTaskLasso, as well as GroupLasso, in the ElasticNet package. Would you consider a valuable addition to the crate?

[YuhanLiin]

You're referring to something like multi-task ElasticNet right? Extending existing algorithms is certainly welcome.

[PABannier]

#194