Updated World class

Added static attributes, and attributes to store the entities on the
World. Updated the constructors (added default world constructor.)
Updated Tick class

Added getters and attributes
Updated StaticEntity class

Added static attributes for default instantiation. Added useful
attributes. Added methods to manipulate the object.
Updated Game Class

Added attributes to define the game. Updated default constructor.
Minor update of the BaseEntity class
Updated AreaEntity

Class completed with attributes, constructor and getter.
Updated ActionMonitor class

Removed attributes (entities/areas)
Updated Action Class

Added static attribute and default action