Update faust_torch module.

- New function torch_Tensor_to_faust_MatDense.
- New prototype tensor_chain_mul(TensorList, MatDense, MatGeneirc, ...)
- New boolean arguments chain_opt and contiguous_dense_to_torch for tensor_chain_mul() functions.
* chain_opt is for calling tensor_chain_mul_opt() internally.
* contiguous_dense_to_torch is for using torch::chain_matmul() to compute intermediary contiguous dense factors.
- Fixing transpose issue for MatDense (defined in column-major order when torch imposes row-major order).