Implemented new_empty()

SGLPPartition, SGPartition, SGShape, SGLabeledShape
Cleaned up sg_labeled_shape

SGLabeledShape.from_shape_and_lpoint_partition(). Deleted
SGLPPartition.from_specs(). Implemented
SGLabeledShape.__eq__(), __ne(). Began
SGLPPartition.__eq__(), __ne(). Began