Initial Erekir tech tree

core/src/mindustry/world/blocks/defense/BuildTurret.java

@@ -46,6 +46,7 @@ public class BuildTurret extends BaseTurret{
 
         //this is super hacky, but since blocks are initialized before units it does not run into init/concurrent modification issues
         unitType = new UnitType("turret-unit-" + name){{
+            hidden = true;
             speed = 0f;
             hitSize = 0f;
             health = 1;