Troops sorting for powerness

At this time the troops sorting menu have only two options 1. rarity and 2. colour. I suggest to add also powerness.

IMHO, powerness would be useful also for sorting the heroes. Powerness is not the power but the difference between the untrained hero respect the actual hero. Those heroes/troops I have trained, I wish to have listed before everyone else.

This change, will introduce the Heroes Roster Organising System suggested changes here in this thread