Fixed a bug in typename dropping references and improving node events.

[GhostofCookie]

Improved Node events by passing the NodeData as a reference to the event instead of forcing events to lookup the data in the event callback. Also fixed TypeName removing reference and const qualifiers from given types. If that behaviour is desired, then TypeName can be called with std::decay_t:

TypeName<int&>::value; // should output "int&"
TypeName<const int&>::value; // should output "const int&"
TypeName<std::decay_t<const int&>>::value; // should output "int"