TensorInv

Added tensorinv function.
Use this:
try: 
   ind = ...
   return [(shapes[0][ind:]+shapes[0][:ind])]
except NotScalar...:
   ind = node.inputs[1]
   sym_shapes = as_tensor_variable(shapes[0])
   return sym_shapes[ind:] + sym_shapes[:ind]

that way, it work correctly.