* Renamed Call Haxe node to Call Function because it will now be able
to call node functions as well.
* Added ability to pass arguments to the Call Function node.
* Created Function and Function output nodes that allow you to create
functions in node trees. Node functions can be called from other nodes
and from Haxe.
Logic node categories are now created dynamically. This allows nodes
be added to any arbitrarily named categories without having to maintain
a global category list. This is useful because it allows custom logic
nodes to be added to custom categories.