Add ability to check if a certain Skill-Tree-node is active or Add activation logic

[Reneator]

Activation logic as in: When the skill-tree-node is learnt, the logic behind it is activated or at least broadcasts its activation. Including an id, so you could have effects/traits etc. that get activated as soon as a skill-node is learnt/active

[Reneator]

I can do the "broadcast" via a global-event to which the developer could connect to or having to add a parent skill-tree or something similar to that.
Possibilities:

• global event
• put nodes in group
• put nodes in group for their skill-tree-node id