fix: livesync should stop when all devices are disconnected

Whenever all devices/emulators/simulators that we are using for LiveSync operation are disconnected or we are unable to sync changes on them, the command (`tns debug`, `tns run`...) should exit.
This is not happening currently due to the setIntervals and iOS device detection that happens and does not stop when the devices are disconnected. So workaround the problem by handling the liveSyncStopped event for the livesync related commands. In case we receive liveSyncStopped for all devices that we've been using for LiveSync action, call process.exit. Use non-zero exit code for this case, as if we receive liveSyncStopped event, we've either received error for particular device or it has been stopped. For both cases this is not a correct behavior for LiveSync.

Author: rosen-vladimirov

lib/common/declarations.d.ts

@@ -596,7 +596,8 @@ declare const enum ErrorCodes {
 	KARMA_FAIL = 130,
 	UNHANDLED_REJECTION_FAILURE = 131,
 	DELETED_KILL_FILE = 132,
-	TESTS_INIT_REQUIRED = 133
+	TESTS_INIT_REQUIRED = 133,
+	ALL_DEVICES_DISCONNECTED = 134
 }
 
 interface IFutureDispatcher {

lib/constants.ts

@@ -1,4 +1,5 @@
 require("colors");
+import { PreviewAppLiveSyncEvents } from "./services/livesync/playground/preview-app-constants";
 
 export const APP_FOLDER_NAME = "app";
 export const APP_RESOURCES_FOLDER_NAME = "App_Resources";
@@ -269,3 +270,13 @@ export class AndroidAppBundleMessages {
 	public static ANDROID_APP_BUNDLE_DOCS_MESSAGE = "What is Android App Bundle: https://docs.nativescript.org/tooling/publishing/android-app-bundle";
 	public static ANDROID_APP_BUNDLE_PUBLISH_DOCS_MESSAGE = "How to use Android App Bundle for publishing: https://docs.nativescript.org/tooling/publishing/publishing-android-apps#android-app-bundle";
 }
+
+export const LiveSyncEvents = {
+	liveSyncStopped: "liveSyncStopped",
+	// In case we name it error, EventEmitter expects instance of Error to be raised and will also raise uncaught exception in case there's no handler
+	liveSyncError: "liveSyncError",
+	previewAppLiveSyncError: PreviewAppLiveSyncEvents.PREVIEW_APP_LIVE_SYNC_ERROR,
+	liveSyncExecuted: "liveSyncExecuted",
+	liveSyncStarted: "liveSyncStarted",
+	liveSyncNotification: "notify"
+};