Commander evolution bufix (#3032)

* Create unit_respawning.lua

This gadget enables unit respawning at a designated target.
This is mainly intended for Evocom.

* hotfix unit_respawning.lua

Made the effigy spawn on the commander.
added 5 second immunity after respawn.
effigy is now destroyed upon commander suicide, unless respawn_pad is true.
Added instructions for iseffigy.

* Hotfix unit_respawning

Added a missing return statement

* hotfix unit_respawning

Fixed a bug preventing the effigy wreck from teleporting to the commanders position.

Added clearing of the commanders commands when respawning.

* Feature Update Unit_Evolution

Added export of target unitID when evolving.

Added options:
new conditions: power, and health
Health transfer: "flat", "percentage", and "full

* Update unit_respawning.lua

Added transfering/replacing of the effigy when evolving, or destruction if the evolution target do not have respawning enabled.

* Update unit_respawning.lua

Added respawn sound

* bugfix unit_evolution

Evolving units should now properly stay in their assigned unit group.

Transports: Time based evolutions will stay on the transport, as long as the evolution target is valid for transport.
Power based evolutions will delay the evolution until disembarked.

* Update unit_evolution.lua

fixes unit group when evolving.

fixes evolving with transports.

luarules/gadgets/unit_evolution.lua

@@ -118,6 +118,7 @@ if gadgetHandler:IsSyncedCode() then
 		local dx, dy, dz = spGetUnitDirection(unitID)
 		local stockpile, stockpilequeued, stockpilebuildpercent = spGetUnitStockpile(unitID)
 		local commandQueue = spGetUnitCommands(unitID, -1)
+		local transporter = Spring.GetUnitTransporter(unitID)
 
 		local newUnitID = spCreateUnit(newUnit, x,y,z, 0, team)
 
@@ -131,7 +132,7 @@ if gadgetHandler:IsSyncedCode() then
 			end
 
 			spSetUnitRulesParam(unitID, "unit_evolved", newUnitID, PRIVATE)
-
+			
 			SendToUnsynced("unit_evolve_finished", unitID, newUnitID, announcement,announcementSize)
 			if evolutionMetaList[unitID].evolution_health_transfer == "full" then
 			elseif evolutionMetaList[unitID].evolution_health_transfer == "percentage" then
@@ -153,6 +154,9 @@ if gadgetHandler:IsSyncedCode() then
 				end
 			end
 
+			if transporter then
+				spGiveOrderToUnit(transporter, CMD.LOAD_UNITS, { newUnitID }, 0)
+			end
 
 			spGiveOrderToUnit(newUnitID, CMD.FIRE_STATE, { states.firestate },             { })
 			spGiveOrderToUnit(newUnitID, CMD.MOVE_STATE, { states.movestate },             { })
@@ -271,6 +275,8 @@ if gadgetHandler:IsSyncedCode() then
 				local enemyCount = -1
 				local teamID = spGetUnitTeam(unitID)
 				local powerValue = 0
+				local transporterID = Spring.GetUnitTransporter(unitID)
+
 				for team, power in pairs(teamPowerList) do
 					if team and teamID and power then
 						local teamsAllied = Spring.AreTeamsAllied(team, teamID)
@@ -286,8 +292,8 @@ if gadgetHandler:IsSyncedCode() then
 					enemyPower = enemyPower/enemyCount
 				end
 				powerValue = powerValue + enemyPower
-
-				if evolutionMetaList[unitID].evolution_condition == "power" and powerValue > evolutionMetaList[unitID].evolution_power_threshold then
+				if transporterID then
+				elseif evolutionMetaList[unitID].evolution_condition == "power" and powerValue > evolutionMetaList[unitID].evolution_power_threshold then
 					local enemyNearby = spGetUnitNearestEnemy(unitID, evolutionMetaList[unitID].combatRadius)
 					local inCombat = false
 					if enemyNearby then
@@ -342,6 +348,10 @@ else
 
 	local function EvolveFinished(cmd, oldID, newID, newAnnouncement, newAnnouncementSize)
 		local selUnits = spGetSelectedUnits()
+		local unitGroup = Spring.GetUnitGroup(oldID)
+		if unitGroup then
+			Spring.SetUnitGroup(newID, unitGroup)
+		end
 		for i=1,#selUnits do
 		  local unitID = selUnits[i]
 		  if (unitID == oldID) then