Initial functionality for expanded KF specific game rules

KFGameRules.uc

/**
 * Expanded set of callbacks specific to Killing Floor events
 * @author etsai
 */
class KFGameRules extends GameRules
    abstract;
  
/**
 * Determines if the perk change should be allowed or not
 * @param   player              Controller of the player who wants to change perks
 * @param   newVeterancyType    Veterancy type to change to
 * @return  True if the player can change to the desired perk, false otherwise
 */
function bool switchPerk(PlayerController player, class<KFVeterancyTypes> newVeterancyType);

/**
 * Determines if the player can purchase the desired weapon
 * @param   player          Controller of the player who wants to change perks
 * @param   weaponClass     Class of the weapon to purchase
 * @return  True if the player can purchase the weapon, false otherwise
 */
function bool purchaseWeapon(PlayerController player, class<Weapon> weaponClass);

/**
 * Indicates that a new wave has just started.  This is only used for wave based games
 * @param   wave    The wave that is starting
 */
function waveStart(int wave);

/**
 * Indicates a wave just ended.  This is only used for wave based games
 * @param   wave    The wave that just ended
 */
function waveEnd(int wave);

/**
 * Indicates a new objective is starting.  This is only used for objective mode
 * @param   objective   Objective that is starting
 */
function objectiveStart(KF_StoryObjective objective);

/**
 * Indicates an objective just ended.  This is only used for objective mode
 * @param   objective   Objective that just ended
 */
function objectiveEnd(KF_StoryObjective objective);