Prevent skewed group image (fixes #756) (#1159)

* Prevent skewed group image (#756)

- fixes #756

//FREEBIE

* Prevent skewed group image in inbox view (#756)

- fix skewed inbox view image
- fixes #756

//FREEBIE

Signal/src/view controllers/InboxTableViewCell.m

@@ -65,6 +65,7 @@
       _timeLabel.attributedText = attributedDate;
 
       if ([thread isKindOfClass:[TSGroupThread class]]) {
+          _contactPictureView.contentMode = UIViewContentModeScaleAspectFill;
           _contactPictureView.image = ((TSGroupThread *)thread).groupModel.groupImage != nil
                                           ? ((TSGroupThread *)thread).groupModel.groupImage
                                           : [UIImage imageNamed:@"empty-group-avatar"];

Signal/src/view controllers/NewGroupViewController.m

@@ -318,6 +318,7 @@ static NSString *const kUnwindToMessagesViewSegue = @"UnwindToMessagesViewSegue"
     _groupImageButton.imageView.layer.masksToBounds = YES;
     _groupImageButton.imageView.layer.borderColor   = [[UIColor lightGrayColor] CGColor];
     _groupImageButton.imageView.layer.borderWidth   = 0.5f;
+    _groupImageButton.imageView.contentMode = UIViewContentModeScaleAspectFill;
 }
 
 #pragma mark - Table view data source