Multiple trees for DRF; rename Tree.java DTree.java

DRF now builds multiple trees in parallel.
DTree now builds & scores multiple trees.
Multi-tree scoring is (hopefully) the proper ensemble method of totalling the predicted classes across all trees, before making any final votes.
Add a covtype DRF test.
Add triple-nested arrays to AutoBuffer.
Multiple trees for DRF; rename Tree.java DTree.java

DRF now builds multiple trees in parallel.
DTree now builds & scores multiple trees.
Multi-tree scoring is (hopefully) the proper ensemble method of
totalling the predicted classes across all trees, before making any
final votes.
Add a covtype DRF test.
Add triple-nested arrays to AutoBuffer.