Core/Unit: rewrite of the attack table system

- Removed a bunch of duplicated code
- Fix off-by-one errors in Unit::RollMeleeOutcomeAgainst and Unit::MeleeSpellHitResult (TC's combat table was actually of 100.01%)
- Implemented boss-level hit table (6.5% dodge/14% parry), bosses only had 5.6% of each until now
- Updated formula for chance and damage of Glancing hits

Sources:
- http://wow.gamepedia.com/index.php?title=Attack_table&oldid=2071465
- http://web.archive.org/web/20100903145646/http://www.mmo-champion.com/threads/650071-Expertise-Hit-for-Paladins-%28updated-for-3.3%29?daysprune=60

src/server/scripts/Spells/spell_dk.cpp

@@ -1727,7 +1727,7 @@ class spell_dk_spell_deflection : public SpellScriptLoader
             void Absorb(AuraEffect* /*aurEff*/, DamageInfo & dmgInfo, uint32 & absorbAmount)
             {
                 // You have a chance equal to your Parry chance
-                if ((dmgInfo.GetDamageType() == SPELL_DIRECT_DAMAGE) && roll_chance_f(GetTarget()->GetUnitParryChance()))
+                if ((dmgInfo.GetDamageType() == SPELL_DIRECT_DAMAGE) && roll_chance_f(GetTarget()->GetFloatValue(PLAYER_PARRY_PERCENTAGE)))
                     absorbAmount = CalculatePct(dmgInfo.GetDamage(), absorbPct);
             }