Fix multiple elements with the same id kata_id_input -> use css class… 

Problem: resume button does not pick up id

I think a problem is that there are several elements with the id "kata_id_input", and so depending on which one jquery reads the value from, you may get the required value, or not.

It seems to vary depending on whether you are running in production mode with compiled assets or not, so it is difficult to reproduce/test locally.

There were a couple of spans that had the same id:kata_id_input as the text input. I changed these to css classes instead.