Unlock tweaks

core/src/mindustry/type/Planet.java

@@ -88,6 +88,8 @@ public class Planet extends UnlockableContent{
                     t.printStackTrace();
                 }
             }
+
+            sectors.random().unlocked = true;
         }else{
             sectors = new Array<>();
         }

core/src/mindustry/type/Sector.java

@@ -21,6 +21,7 @@ public class Sector{
     public final SectorData data;
 
     public @Nullable SaveSlot save;
+    public boolean unlocked;
 
     //TODO implement a dynamic (?) launch period
     public int launchPeriod = 10;
@@ -35,7 +36,7 @@ public class Sector{
     }
 
     public boolean locked(){
-        return true;
+        return !unlocked;
     }
 
     /** @return light dot product in the range [0, 1]. */

core/src/mindustry/ui/dialogs/PlanetDialog.java

@@ -213,7 +213,7 @@ public class PlanetDialog extends FloatingDialog{
         batch.proj().mul(planet.getTransform(mat));
 
         for(Sector sec : planet.sectors){
-            if(sec.save == null){
+            if(sec.locked()){
                 draw(sec, shadowColor, -0.001f);
             }
         }