Add function to reinitialise / resize / recreate tensor

[axsaucedo]

Currently once the tensor is created, the size of the vector is fixed and there is no option to reshape or recreate. If new data is passed which is different size (or if it's required to re-configure a tensor to use a new array size), it is not possible. It should be made possible to resize and re-initialise tensors, whether directly through the OpCreateTensor or through a new operation.