An issue about the implement of train_scpn.py forward function

[shuangqinbuaa]

The line 241 in train_scpn.py:
copy_probs = copy_probs.view(-1);
I think it should be:
copy_probs = copy_probs.transpose(0, 1).contiguous().view(-1)
because decoder_states, decoder_copy_dists are transposed:
line 234: decoder_states = decoder_states.transpose(0, 1).contiguous().view(-1, self.d_hid * 2)
line 238: decoder_copy_dists = decoder_copy_dists.transpose(0, 1).contiguous().view(-1, self.len_voc)
@miyyer @jwieting