refactor!: Un-export Timer (#90)

This PR removes the internal `Timer` class from the exports. It is a
very simple wrapper over the `Stopwatch` API and does not provide any
additional functionality. But it does causes conflicts when try to use
Flame's `Timer` or dart:async's `Timer`. By not exporting it, we can
save the users from these conflicts.

packages/forge2d/example/web/demo.dart

@@ -1,7 +1,7 @@
 import 'dart:async';
 import 'dart:html' hide Body;
 
-import 'package:forge2d/forge2d_browser.dart' hide Timer;
+import 'package:forge2d/forge2d_browser.dart';
 
 /// An abstract class for any Demo of the Forge2D library.
 abstract class Demo {

packages/forge2d/lib/src/common.dart

@@ -2,6 +2,5 @@ export 'common/color3i.dart';
 export 'common/raycast_result.dart';
 export 'common/rot.dart';
 export 'common/sweep.dart';
-export 'common/timer.dart';
 export 'common/transform.dart';
 export 'common/viewport_transform.dart';

packages/forge2d/lib/src/dynamics/world.dart

@@ -5,6 +5,7 @@
 import 'dart:math';
 
 import 'package:forge2d/forge2d.dart';
+import 'package:forge2d/src/common/timer.dart';
 import 'package:forge2d/src/settings.dart' as settings;
 
 /// The world class manages all physics entities, dynamic simulation, and

packages/forge2d/pubspec.yaml

@@ -7,11 +7,11 @@ environment:
   sdk: ">=3.0.0 <4.0.0"
 
 dependencies:
-  meta: ^1.9.1
+  meta: ^1.11.0
   vector_math: ^2.1.4
 
 dev_dependencies:
   dartdoc: ^7.0.2
   flame_lint: ^1.1.1
   mocktail: ^1.0.1
-  test: any
+  test: ^1.24.9