Cleanup months and weeks translations

Removed the translations of months and weeks from the Scheduler bundle
since they were already translated in Locale files.
 - The a3_<month> strings were removed (replaced by
   NSShortMonthNameArray)
- The months strings were removed (replaced by NSMonthNameArray)
- The weeks strings were removed (replaced by NSWeekDayNameArray)

Moved the a2_<weekday> strings to the Common bundle and added a new
method [UIxComponent commonLabelForKey:].

UI/PreferencesUI/UIxPreferences.h

@@ -26,7 +26,6 @@
 #import <SOGoUI/UIxComponent.h>
 
 @class NSString;
-@class SOGoUserDefaults;
 
 @class SOGoUser;
 
@@ -34,13 +33,11 @@
 {
   id item;
   SOGoUser *user;
-  NSDictionary *locale;
   NSString *category;
   NSArray *calendarCategories;
   NSDictionary *calendarCategoriesColors;
   NSArray *contactsCategories;
   NSString *defaultCategoryColor;
-  SOGoUserDefaults *userDefaults;
   NSCalendarDate *today;
   NSArray *daysOfWeek, *daysBetweenResponsesList;
   NSArray *sieveFilters;