Changes to Pathauto

I've reviewed the current state of the pathauto module. 
As I'm new to D8 development, I did some minor changes I saw during the reading of the code.
I've looked at it more closely, and the module file is no good place at all because that would lead to code duplication on many places where ``PathautoManager::updateAlias`` is issued. I'm not sure what would be a good place though..