Fixed Bugs and Added Train Loss Dump Feature

[alexeevrevan]

1) I've added the feature that saveы the average train loss after every epoch into sгmmary in order to visualise results after the training is done

2) The program now shows the best CER correctly.

3) I've written "No improvments for" instead of "No improvments since", because it is more appropriate way to define the distance in English

[githubharald]

thanks for the contribution, I'll try to have a look in the next few days 👍

[githubharald]

merged. thanks for your contribution.