Echo().execute(message) is now just Echo(message)

Former-commit-id: 851e141fc91b170190d6027f42f59906dda0f31f
Former-commit-id: 03dbb9da1788e1c50e84ae33d95f76194ad9a08d

src/net/torvald/terrarum/console/SpawnPhysTestBall.kt

@@ -33,6 +33,6 @@ internal object SpawnPhysTestBall : ConsoleCommand {
     }
 
     override fun printUsage() {
-        Echo.execute("usage: spawnball [elasticity]")
+        Echo("usage: spawnball [elasticity]")
     }
 }