Game server/skill system: increased MAGIC_TYPE4.ExpPct to 2 bytes (smallint) as one new case exceeded a byte. Added MAGIC_TYPE4.SpecialAmount (the last column in the new skill_magic_4.tbl) which some skills refer to generically similar to ExpPct (replaced the cases where we had it using ExpPct, instead of this new column -- buff type 48 uses it also).