Event-driven dialog queue, story flag command, mod unit tests

Push-based event chains, runtime fixes (single end, goto lifecycle, if,
busy box, held delay, empty options, timed/animated/effect actions), the
'flag name value' DSL command, autoplay --dialogs=N, 19 mod unit tests.

tests/ExecutableEventTests.cs

@@ -0,0 +1,44 @@
+namespace Cthangover.Mods.Dialog.Tests
+{
+    using System.Threading.Tasks;
+    using Cthangover.Core.Mods.Testing;
+    using Cthangover.Core.Scenes;
+    using Cthangover.Mods.Dialog.Executable;
+
+    /// <summary>
+    /// A standalone <see cref="ExecutableEvent"/> (not inside a chain): a run the dialog
+    /// box refused is not counted, and the event starts by itself on the next state
+    /// change, without polling.
+    /// </summary>
+    public class ExecutableEventTests
+    {
+        [ModTest("event/refused_run_is_not_counted", TimeoutSeconds = 10)]
+        static async Task RefusedRunIsNotCounted(ModTestContext ctx)
+        {
+            var stage = await DialogStage.Create();
+            try
+            {
+                stage.Box.IsActive = false;
+                var evt = new ScenarioEvent { ScenarioText = "text \"S\"", ScenarioId = "dialog_base_test_standalone", IsOneRun = true };
+                stage.Host.AddChild(evt);
+                await DialogStage.Frames(2);
+
+                ModAssert.False(stage.Box.IsRunning, "inactive box refused the event");
+                ModAssert.True(evt.IsFirstRun, "refused automatic run is not counted");
+                ModAssert.False(evt.RunDialog(), "direct run is refused too");
+                ModAssert.True(evt.IsFirstRun, "refused direct run is not counted");
+
+                stage.Box.IsActive = true;
+                ConditionStateMonitor.MarkStateChanged();
+                await DialogStage.Frames(2);
+
+                ModAssert.True(stage.Box.Locker == evt, "one-run event starts on the next state change");
+                ModAssert.False(evt.IsFirstRun, "the real run is counted");
+            }
+            finally
+            {
+                stage.Free();
+            }
+        }
+    }
+}