Correction of a trainer influence bug

We were recently made aware of a flaw in our implementation of trainers.

The flaw meant that employees with the 'scout' specialisation were equally good at training players as employees with the 'trainer' specialisation.

That obviously doesn't make a whole lot of sense, so we have now fixed the bug. From now on, if you use a scout as a trainer, his influence on the training results will only be half as good as an actual specialised trainer with equal stats.