genrep: remove trailing newline for Firefox
genrep: remove trailing newline for Firefox

this was surprisingly difficult: I had to use the fact that `printf`
won't print a trailing newlines unless told to (as mentioned in
mklemento0's answer on a Stack Overflow question
[here](http://stackoverflow.com/a/12148703/2246637).

raehik/aqa-computing,raehik/aqa-computing,raehik/aqa-computing,raehik/aqa-computing