add hierarchy model definition
add hierarchy model definition
Merge remote-tracking branch 'origin/googlenet' into googlenet
 fixed a bug for accuracy tree
modified the tree layers to enable overlapping childs
Merge branch 'tree' into mpi_parallel

Conflicts:
	models/bvlc_reference_caffenet/solver.prototxt
	models/bvlc_reference_caffenet/train_val.prototxt
	models/googlenet/solver.prototxt
	models/googlenet/train_val4.prototxt
	models/hierarchical10/solver.prototxt
	models/hierarchical10/train_val.prototxt
	models/new_googlenet/solver.prototxt
	models/new_googlenet/train_val4.prototxt
	models/two_layer_tree/solver.prototxt
	models/two_layer_tree/train_val_small.prototxt
fixed a bug for overlapping loss tree