New config variable dayz_toolBreaking

Tool breaking is disabled by default.

Also made all scripts use Epoch sledge, which is a different model from
vanilla sledge.

PK_DZ was a duplicate of the new PKM_DZ.

SQF/dayz_code/actions/player_chopWood.sqf

@@ -102,7 +102,7 @@ if (_woodCutting) then {
 
         if(_finished) then {                
             _breaking = false;
-            if ([0.04] call fn_chance) then {
+            if (dayz_toolBreaking && {[0.04] call fn_chance}) then {
                 _breaking = true;
                 if ("MeleeHatchet" in weapons player) then {
                     player removeWeapon "MeleeHatchet";