Troop Filter Improvements

A couple of ideas for making it easier to find troops:

  • I’d like to be able to sort by mana requirement, low to high by default.
  • I’d like to be able to tag troops as “favourites” and use it to restrict searches, possibly as a troop type.

Definitely want a favorites thing. Standard feature, tag the troops with a star in an unoccupied bit of space.