Research system progress

core/src/mindustry/io/SaveVersion.java

@@ -6,6 +6,7 @@ import arc.struct.*;
 import arc.util.*;
 import arc.util.io.*;
 import mindustry.content.*;
+import mindustry.content.TechTree.*;
 import mindustry.core.*;
 import mindustry.ctype.*;
 import mindustry.game.*;
@@ -75,6 +76,11 @@ public abstract class SaveVersion extends SaveFileReader{
             state.secinfo.prepare();
         }
 
+        //flush tech node progress
+        for(TechNode node : TechTree.all){
+            node.save();
+        }
+
         writeStringMap(stream, StringMap.of(
             "saved", Time.millis(),
             "playtime", headless ? 0 : control.saves.getTotalPlaytime(),