Switched Shield Wall and Repulsion

Shield Wall now reduces damage done by 20% instead of reducing attack/damage by flat values, making it more usefull at lower levels
Armour values are no more flat reductions of damage, instead armor deducts a % of the incomming damage, this means that super high armour values can not cheese out some npcs but no npc can cheese out the player either
APR follows the same idea as armour


git-svn-id: http://svn.net-core.org/repos/t-engine4@2790 51575b47-30f0-44d4-a5cc-537603b46e54