Implemented censored names preference

Added case sensitivity preference
Integer tags are not clearable anymore

TagTunes/Preferences.swift

@@ -8,6 +8,15 @@
 
 import Cocoa
 
+/// Internal class to be used in IB to bind to the shared preferences.
+@objc internal class PreferencesSingleton: NSObject {
+    
+    internal dynamic var sharedPreferences: Preferences {
+        return Preferences.sharedPreferences
+    }
+    
+}
+
 /// A custom interface for the `NSUserDefaults`. It is recommended to use this
 /// class insted of accessing the user defaults directly to prevent errors due
 /// to misspelled strings.
@@ -17,7 +26,7 @@ import Cocoa
 
     // MARK: Types
     
-    private struct UserDefaultsConstants {
+    internal struct UserDefaultsConstants {
     
         static let saveArtworkKey = "Save Artwork"
         
@@ -29,6 +38,8 @@ import Cocoa
         
         static let useCensoredNamesKey = "Use Censored Names"
         
+        static let caseSensitive = "Case Sensitive"
+        
         static let tagSavingBehaviorsKey = "Tag Saving Behaviors"
     }
     
@@ -58,7 +69,8 @@ import Cocoa
             UserDefaultsConstants.saveArtworkKey: false,
             UserDefaultsConstants.keepSearchResultsKey: false,
             UserDefaultsConstants.removeSavedAlbumsKey: false,
-            UserDefaultsConstants.useCensoredNamesKey: false
+            UserDefaultsConstants.useCensoredNamesKey: false,
+            UserDefaultsConstants.caseSensitive: true
             ])
         if NSUserDefaults.standardUserDefaults().dictionaryForKey(UserDefaultsConstants.tagSavingBehaviorsKey) == nil {
             var savingBehaviors: [Track.Tag: TagSavingBehavior] = [:]
@@ -122,6 +134,16 @@ import Cocoa
         }
     }
     
+    /// If `true` TagTunes ignores cases when comparing track titles and albums.
+    public dynamic var caseSensitive: Bool {
+        set {
+            NSUserDefaults.standardUserDefaults().setBool(newValue, forKey: UserDefaultsConstants.caseSensitive)
+        }
+        get {
+            return NSUserDefaults.standardUserDefaults().boolForKey(UserDefaultsConstants.caseSensitive)
+        }
+    }
+    
     /// The ways different tags are saved (or not saved).
     public var tagSavingBehaviors: [Track.Tag: TagSavingBehavior] {
         set {