Fix a few Lua 5.3-related errors

Reported on bay12:
http://www.bay12forums.com/smf/index.php?topic=164123.msg7821831#msg7821831

docs/changelog.txt

@@ -39,8 +39,10 @@ changelog.txt uses a syntax similar to RST, with a few special sequences:
 
 ## Fixes
 - `building-hacks`: fixed error when dealing with custom animation tables
+- `devel/test-perlin`: fixed Lua error (``math.pow()``)
 - `embark-assistant`: fixed crash when entering finder with a 16x16 embark selected, and added 16 to dimension choices
 - `prospector`: (also affected `embark-tools`) - fixed a crash when prospecting an unusable site (ocean, mountains, etc.) with a large default embark size in d_init.txt (e.g. 16x16)
+- `siege-engine`: fixed a few Lua errors (``math.pow()``, ``unit.relationship_ids``)
 
 ## Misc Improvements
 - `devel/export-dt-ini`: added viewscreen offsets for DT 40.1.2

plugins/lua/siege-engine.lua

@@ -163,7 +163,7 @@ function getBaseUnitWeight(unit)
         rv = rv * 3
     elseif unit.job.destroy_target then
         rv = rv * 2
-    elseif unit.relations.group_leader_id < 0 and not flags1.rider then
+    elseif unit.relationship_ids.GroupLeader < 0 and not flags1.rider then
         rv = rv * 1.5
     end
 
@@ -172,7 +172,7 @@ end
 
 function getUnitWeight(unit)
     local base = getBaseUnitWeight(unit)
-    return base * math.pow(0.7, recent_targets[unit.id] or 0)
+    return base * (0.7 ^ (recent_targets[unit.id] or 0))
 end
 
 function unitWeightCache()
@@ -200,7 +200,7 @@ function scoreTargets(engine, reachable)
     computeNearbyWeight(engine, reachable, ucache)
 
     for _,tgt in ipairs(reachable) do
-        tgt.score = (tgt.score + tgt.nearby_weight*0.7) * math.pow(0.995, tgt.time/3)
+        tgt.score = (tgt.score + tgt.nearby_weight*0.7) * (0.995 ^ (tgt.time/3))
     end
 
     table.sort(reachable, function(a,b)

scripts

@@ -1 +1 @@
-Subproject commit 66b39d888e5f2d4f5c194ece08ba62ac7f110478
+Subproject commit 87cc0fcad57a3a8ff7b558be9f3523101ac2f69d