Lizard: Better tree crown looks
Bugfixes for double representation
Minor refactoring of birdhero and lizard
Super class for Number Panel Subgames added

The number panel subgames (birdhero, lizard and bee) all rely on the
same mechanics, so this is an attempt to reconcile shared code in a
super class.
Here Birdhero has been updated for the new super class.
Lizard: Use new number panel super class

Note: The different methods have only been added as placeholders.
ButtonPanel: Bugfix for update buttons
Birdhero: Do not call tryNumber unnecessarily
Lizard: Methods added

The lizard will now get stuck when appropriate
Agent: Bugfix for guessing graphics
NPSubgames now have method relative agent guess
Moved thinking to character instead of agent
Lizard: Add/Subt method added
Agent guess bugfix for relative values
Birdhero: Add/Subt method added