minor fixes on Playgrounds and Demo app

CoreStoreDemo/CoreStoreDemo/Loggers Demo/CustomLoggerViewController.swift

@@ -16,11 +16,6 @@ class CustomLoggerViewController: UIViewController, CoreStoreLogger {
     
     // MARK: NSObject
     
-    deinit {
-        
-        CoreStore.logger = DefaultLogger()
-    }
-    
     let dataStack = DataStack()
     
     // MARK: UIViewController
@@ -30,13 +25,14 @@ class CustomLoggerViewController: UIViewController, CoreStoreLogger {
         super.viewDidLoad()
         
         try! self.dataStack.addStorageAndWait(SQLiteStore(fileName: "emptyStore.sqlite"))
-        CoreStore.logger = self
     }
     
     override func viewDidAppear(_ animated: Bool) {
         
         super.viewDidAppear(animated)
-        
+
+        CoreStore.logger = self
+
         let alert = UIAlertController(
             title: "Logger Demo",
             message: "This demo shows how to plug-in any logging framework to CoreStore.\n\nThe view controller implements CoreStoreLogger and appends all logs to the text view.",
@@ -46,6 +42,13 @@ class CustomLoggerViewController: UIViewController, CoreStoreLogger {
         self.present(alert, animated: true, completion: nil)
     }
 
+    override func viewDidDisappear(_ animated: Bool) {
+
+        super.viewDidDisappear(animated)
+
+        CoreStore.logger = DefaultLogger()
+    }
+
     
     // MARK: CoreStoreLogger
     

Playground.playground/Contents.swift

@@ -14,7 +14,6 @@ class Person: CoreStoreObject {
 }
 /// =======================
 
-
 /// Stack setup ===========
 let dataStack = DataStack(
     CoreStoreSchema(
@@ -28,7 +27,6 @@ let dataStack = DataStack(
 try dataStack.addStorageAndWait(SQLiteStore(fileName: "data.sqlite"))
 /// =======================
 
-
 /// Transactions ==========
 dataStack.perform(synchronous: { transaction in
 
@@ -42,7 +40,6 @@ dataStack.perform(synchronous: { transaction in
 })
 /// =======================
 
-
 /// Accessing Objects =====
 let bird = dataStack.fetchOne(From<Animal>().where(\.species == "Sparrow"))!
 bird.species.value

Playground.playground/timeline.xctimeline

@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<Timeline
-   version = "3.0">
-   <TimelineItems>
-   </TimelineItems>
-</Timeline>