Make it easier to tell why you cannot evolve something

[magroader]

There is confusion when things cannot evolve because they don't have the right move or aren't the right gender (while strict genders is on).

The check to see whether something can evolve could also return, when they cannot, WHY they cannot. We could then allow the evolve button to be pressed, but do a popup explaining why evolution is not currently possible ("Cannot evolve: no gender set", "Cannot evolve, must be level 8")