Allow skynet properties override and improve dead unit handling

Now the user can override special skynet properties from the unit.yaml of the main Radar of the sam site. Which unit needs these overrides can be looked up over here: https://github.com/walder/Skynet-IADS/blob/develop/skynet-iads-source/skynet-iads-supported-types.lua

- fixed wrong exclusion of groups with the first unit dead but still able to participate
- added some exception handling in the lua script for groups which skynet is not able to control. preventing scripting errors

resources/plugins/skynetiads/skynetiads-config.lua

@@ -40,6 +40,28 @@ if dcsLiberation and SkynetIADS then
 
     -- actual configuration code
     local function initializeIADSElement(iads, iads_unit, element)
+        if iads_unit == nil then
+            -- skip processing of units which can not be handled by skynet
+            return
+        end
+        if element.engagement_zone then
+            iads_unit:setEngagementZone(element.engagement_zone)
+        end
+        if element.can_engage_harm then
+            iads_unit:setCanEngageHARM(element.can_engage_harm)
+        end
+        if element.harm_detection_chance then
+            iads_unit:setHARMDetectionChance(tonumber(element.harm_detection_chance))
+        end
+        if element.can_engage_air_weapon then
+            iads_unit:setCanEngageAirWeapons(element.can_engage_air_weapon)
+        end
+        if element.go_live_range_in_percent then
+            iads_unit:setGoLiveRangeInPercent(tonumber(element.go_live_range_in_percent))
+        end
+        if element.autonomous_behaviour then
+            iads_unit:setAutonomousBehaviour(element.autonomous_behaviour)
+        end
         if element.ConnectionNode then
             for i,cn in pairs(element.ConnectionNode) do
                 env.info(string.format("DCSLiberation|Skynet-IADS plugin - adding IADS ConnectionNode %s", cn))