Feature/epub title in navbar (#281)

* Update realm to 3.0.2

Updating realm to version 3.0.2, All features seem to be working fine. I have also removed the forced versioning for realm. Any realm updates from from now on should automatically be applied upon using pod install or pod update. All future updates should also be compatible by nature so it should not have to be locked down again.
#278

* Added epub titles to navbar

Added configuration variable to allow dev to display or hide current epub file's title in the navbar.
Added config variable to example project.

Example/Example/ViewController.swift

@@ -33,6 +33,7 @@ class ViewController: UIViewController {
         // See more at FolioReaderConfig.swift
 //        config.canChangeScrollDirection = false
 //        config.enableTTS = false
+//        config.displayTitle = true
 //        config.allowSharing = false
 //        config.tintColor = UIColor.blueColor()
 //        config.toolBarTintColor = UIColor.redColor()

Source/FolioReaderCenter.swift

@@ -268,6 +268,10 @@ open class FolioReaderCenter: UIViewController, UICollectionViewDelegate, UIColl
 
         rightBarIcons.append(contentsOf: [font])
         navigationItem.rightBarButtonItems = rightBarIcons
+
+        if(self.readerConfig.displayTitle){
+            navigationItem.title = book.title()
+        }
     }
 
     func reloadData() {

Source/FolioReaderConfig.swift

@@ -140,6 +140,9 @@ open class FolioReaderConfig: NSObject {
 
     /// Enable TTS (Text To Speech)
     open var enableTTS = true
+
+    /// Display book title in navbar
+    open var displayTitle = false
 
     // hide the page indicator
     open var hidePageIndicator = false