Fix static initialization of godot binding classes

[dazKind]

static var test : godot.variant.StringName = "crash"; will crash since Haxe's static initialization happens before Godot-Classes are registered. We need to some macro handler to deal with these static fields and do the initialization upon successful class registration

[dazKind]

For the moment we added a compiler warning, but we want a proper handler for this

[dazKind]

Should be fixed in 9ea230a

We run a custom routine now.

package example;
import godot.variant.StringName;
import godot.variant.NodePath;

class HxOther extends godot.Node {

    // the following will use new static initialization routine
    static var someStringName:StringName = "test2"; 
    static var someNodePath = new NodePath();

    override function _ready() {
        trace(someStringName);
    }
}

[dazKind]

Review in case of ScriptLanguageExtension