Modified Reshape to auto compute output size.
Modified Reshape to auto compute output size.

- the size can be specified in an abstract way now:
  for example, n = nn.Reshape(1,-1,-1) will reshape
  any 2D tensor into a 3D tensor: HxW -> 1xHxW.

- copies are also avoiding, the output is now a view
  of the input.

soumith/TH,soumith/TH,soumith/TH,soumith/TH