AEGIS 'Class_' system.

* Deleted RC_BOSS, RC_NONBOSS, RC_NONDEMIHUMAN.
* Added new enum with:
 - CLASS_NORMAL( for all players, elementals, homuns, mercenaries & normal mobs )
 - CLASS_BOSS( for boss type monsters )
 - CLASS_GUARDIAN( for guardian type monsters )
* Updated/added item bonuses.

What do you think about this?