UIBarButtonItem+Theme: replace deprecated API

Sources/UIBarButtonItem+Theme.m

@@ -2,7 +2,7 @@
  * UIBarButtonItem+Theme.m
  * VLC for iOS
  *****************************************************************************
- * Copyright (c) 2013-2015 VideoLAN. All rights reserved.
+ * Copyright (c) 2013-2017 VideoLAN. All rights reserved.
  * $Id$
  *
  * Authors: Felix Paul Kühne <fkuehne # videolan.org>
@@ -16,7 +16,7 @@
 + (UIBarButtonItem *)themedBackButtonWithTarget:(id)target andSelector:(SEL)selector
 {
     UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithTitle:NSLocalizedString(@"BUTTON_BACK", nil)
-                                                                   style:UIBarButtonItemStyleBordered
+                                                                   style:UIBarButtonItemStylePlain
                                                                   target:target
                                                                   action:selector];
     backButton.tintColor = [UIColor whiteColor];
@@ -33,16 +33,15 @@
      * Note: this icon doesn't represent an endorsement of The Coca-Cola Company
      * and should not be confused with the idea of religious statements or propagation there off
      */
-    NSCalendar *gregorian =
-    [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
-    NSUInteger dayOfYear = [gregorian ordinalityOfUnit:NSDayCalendarUnit inUnit:NSYearCalendarUnit forDate:[NSDate date]];
+    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
+    NSUInteger dayOfYear = [gregorian ordinalityOfUnit:NSCalendarUnitDay inUnit:NSCalendarUnitYear forDate:[NSDate date]];
     UIImage *icon;
     if (dayOfYear >= 354)
         icon = [UIImage imageNamed:@"vlc-xmas"];
     else
         icon = [UIImage imageNamed:@"menuCone"];
 
-    UIBarButtonItem *menuButton = [[UIBarButtonItem alloc] initWithImage:icon style:UIBarButtonItemStyleBordered target:target action:selector];
+    UIBarButtonItem *menuButton = [[UIBarButtonItem alloc] initWithImage:icon style:UIBarButtonItemStylePlain target:target action:selector];
     menuButton.tintColor = [UIColor whiteColor];
     menuButton.accessibilityLabel = NSLocalizedString(@"OPEN_VLC_MENU", nil);
 
@@ -51,7 +50,7 @@
 
 + (UIBarButtonItem *)themedDarkToolbarButtonWithTitle:(NSString*)title target:(id)target andSelector:(SEL)selector
 {
-    UIBarButtonItem *button = [[UIBarButtonItem alloc] initWithTitle:title style:UIBarButtonItemStyleBordered target:target action:selector];
+    UIBarButtonItem *button = [[UIBarButtonItem alloc] initWithTitle:title style:UIBarButtonItemStylePlain target:target action:selector];
     button.tintColor = [UIColor whiteColor];
 
     return button;