acoustic modeling fails with features AND deltas

[mmmaat]

• problem: Acoustic modeling fails when built on features with deltas. This causes a "bad features dimension" error. The AM Kaldi recipe expect the input features to have no deltas (they are automatically computed within the recipe)

• solution 1: A fast and dirty fix would be to detect the presence of deltas in the input features during AM init, and output a user friendly user message.

• solution 2: Best but more work invloved! modify the recipe to consider deltas if they are already here...