Don't show the early launcher GUI when running data. It's not needed and prevents use on automated builds.

Need to investigate why a bunch of tags seem to be being blown away by rerunning on forge.

Signed-off-by: cpw <cpw+github@weeksfamily.ca>

src/userdev/java/net/minecraftforge/userdev/FMLDevDataLaunchProvider.java

@@ -64,4 +64,8 @@ public class FMLDevDataLaunchProvider extends FMLDevServerLaunchProvider impleme
         return "mcp";
     }
 
+    @Override
+    public boolean isData() {
+        return true;
+    }
 }

src/userdev/java/net/minecraftforge/userdev/FMLUserdevDataLaunchProvider.java

@@ -58,4 +58,9 @@ public class FMLUserdevDataLaunchProvider extends FMLUserdevLaunchProvider imple
     {
         return Dist.CLIENT;
     }
+
+    @Override
+    public boolean isData() {
+        return true;
+    }
 }