Random Forest added

- Random Forest added

[Reference](http://www.stat.berkeley.edu/~breiman/RandomForests/cc_home.htm#overview)
From the beginning of this method up until here, this method is the same as the one that is overloading in its parent class :-) I think that only the `REQUIRE` in line 63 has been added here. Put common functionality in a method that can be called from both classes, please.