Necromancer Fix for D2RMM

Just a couples of tweaks for necromancer class, this mod make all curses increased range per level of skill and Poison Dagger skill now works even with wands, completely reworked Poison Explosion, now work like Teeth but the damage is poison infection that make damage for the duration of the skill. The damage description may be not properly correct but damage and duration of new Poison Explosion is same vanilla.