Implemented a PointMesh class that is used by class HeatActuatorMesh.
The PointMesh class provides methods to created 3 types of meshes: ring, circle, and circumference.

CASU peltier is a circumference of 16 points.

Class ExtendedWorld has a first version to save the world state to a file. Currently only heat is saved.

Added an option to file Playground.cfg to specify whether the world state is saved or not.