Sublayer -> Affine and Transfer Layers

Split Sublayer into AffineLayer and TransferLayer. Sublayer should no
longer be used from now on.

AffineLayer can have multiple Affine objects within it.
Implemented merge_by_block, but not merge_by_node.

Next step: implement Layer, which will have AffineLayer with
TransferLayer.
Merge branch 'master' of https://github.com/wongliangze/drunken-ironman

Conflicts:
	NeuralNet/test_grad.pyc