Stage 1 of clang compiler warning patches.

UI/MailerUI/UIxMailFolderActions.m

@@ -451,7 +451,7 @@
   NSMutableDictionary *moduleSettings, *threadsCollapsed;
   NSMutableArray *mailboxThreadsCollapsed;
   NSString *destinationFolder;
-  SOGoUserSettings *us;
+  SOGoUserSettings *us=nil;
   WOResponse *response;
   NSDictionary *data;
   SOGoMailFolder *co;

UI/MailerUI/UIxMailMainFrame.m

@@ -620,7 +620,7 @@
 
 - (NSString *) columnsDisplayCount
 {
-  return [NSString stringWithFormat: @"%d", [[self columnsDisplayOrder] count]];
+  return [NSString stringWithFormat: @"%d", (int)[[self columnsDisplayOrder] count]];
 }
 
 - (void) setCurrentColumn: (NSDictionary *) newCurrentColumn

UI/MailerUI/UIxMailView.m

@@ -57,6 +57,7 @@
 #import <Mailer/SOGoMailFolder.h>
 #import <MailPartViewers/UIxMailRenderingContext.h> // cyclic
 #import <MailPartViewers/UIxMailSizeFormatter.h>
+#import <MailPartViewers/UIxMailPartViewer.h>
 
 #import "WOContext+UIxMailer.h"
 #import "UIxMailFormatter.h"
@@ -229,7 +230,7 @@ static NSString *mailETag = nil;
 
 - (id <WOActionResults>) defaultAction
 {
-  id <WOActionResults> response;
+  WOResponse *response;
   NSString *s;
   NSMutableDictionary *data;
   NSArray *addresses;