Append new trees to ensemble
B = append(B,other)
B = append(B,other) appends the trees from the other ensemble to those in B. This method checks for consistency of the X and Y properties of the two ensembles, as well as consistency of their compact objects and out-of-bag indices, before appending the trees. The output ensemble B takes training parameters such as FBoot, Prior, Cost, and other from the B input. There is no attempt to check if these training parameters are consistent between the two objects.