Fixed ReaderModel#isInitialized state

src/main/java/com/kdanmobile/reader/ReaderModel.kt

@@ -40,7 +40,7 @@ class ReaderModel {
         this.kmpdfFactory = kmpdfFactory
         this.filename = filename
         this.password = password
-        this.isInitialized = false
+        this.isInitialized = true
     }
 
     fun initKMPDFDocumentController() {
@@ -50,6 +50,7 @@ class ReaderModel {
 
     @Synchronized
     fun destroy() {
+        isInitialized = false
         filename = null
         password = ""
         kmpdfFactory?.onDestroy()