Unnecessary GPU memory usage in PyTorch Implementation

[tinyRattar]

I noticed that in main_crnn.py, line 167 : validate_err += err as err is a Varaible on GPU, such usage will take extra GPU memory (with PyTorch 1.0.1), maybe you should use err.item() instead like line 147. line 188 has the same problem as well

[Alxemade]

Thanks!