Changed health bar to display the actual health.
Changed health bar color to match.
Added "permanent" property to ObjectBase to mark that the object cannot be hurt or destroyed (ObjectPlayer1Switch for example).
Added ObjectBase.on_hit() and hit_nearby_objects() to handle the damage caused by an object.
Added attack_status, attack_ammo, attack_cycle_time, attack_reload_time to ObjectPlayer2Base and made them constructor parameters.
Added GUI bars for the new parameters of ObjectPlayer2*.
Added reload-cycle-ready progress to ObjectPlayer2Base.on_tick().
Added ObjectPlayer2Base.on_ready_to_attack().
Added a dummy attack-everyone-always attack to ObjectPlayer2Base.on_ready_to_attack().