We now allow booleanization of all types. This means that empty versions
of all types now evaluate to false. So a Vector2(0,0), Dictionary(),
etc.
This allows you to write GDScript like:
if not Dictionary():
print("Empty dict")
Booleanization can now also no longer fail. There is no more valid flag,
this changes Variant and GDNative API.
Hein-Pieter van Braam
833c3917b2