[Add] Empty StarSystem and made ai use it!

dat/ssys.xml

@@ -23,6 +23,7 @@
 			<fleet chance="40">Sml Merchant Convoy</fleet>
 		</fleets>
     <jumps>
+			<jump>NCG-7291</jump>
       <jump>SaraSys</jump>
     </jumps>
 </ssys>
@@ -45,6 +46,30 @@
 			<fleet chance="60">Merchant Ship</fleet>
 		</fleets>
     <jumps>
+			<jump>NCG-7291</jump>
+      <jump>KonoSys</jump>
+    </jumps>
+	</ssys>
+	<ssys name="NCG-7291">
+		<pos>
+			<x>23</x>
+			<y>24</y>
+		</pos>
+		<general>
+			<stars>230</stars>
+			<asteroids>0</asteroids>
+			<interference>0</interference>
+		</general>
+		<planets>
+		</planets>
+		<fleets>
+			<fleet chance="80">Merchant Ship</fleet>
+			<fleet chance="60">Merchant Mule</fleet>
+			<fleet chance="60">Pirate</fleet>
+			<fleet chance="60">Pirate</fleet>
+		</fleets>
+    <jumps>
+			<jump>SaraSys</jump>
       <jump>KonoSys</jump>
     </jumps>
 	</ssys>

scripts/ai/merchant.lua

@@ -12,7 +12,12 @@ function control()
 		end
 	elseif task == "none" then
     planet = ai.rndplanet()
-    ai.pushtask(0, "go", planet)
+		-- Planet must exist.
+		if planet == nil then
+			ai.pushtask(0, "hyperspace")
+		else
+    	ai.pushtask(0, "go", planet)
+		end
   end
 end