New: Fails on failing preconditions

[matthias-mayr]

A skill (description) will fail instead of being idle. If it is only idle, there is little feedback for the user and the GUI gets stuck. Credits go to Pontus Rosqvist.

From a normal user perspective, this is a very useful change. However I am not quite sure what the idle state means. Maybe this change has implications that I am not seeing.

[frvd]

Since the tree fails instead of hanging, it could affect trees that rely on some branches to hang until a precondition becomes valid. But logically this change makes sense and should be merged. @matthias-mayr will you merge it after you checked for potentially affected skills?

[matthias-mayr]

I am not aware of any skill that makes use of this, especially not one that is publicly available.

[matthias-mayr]

Wrong button -.-