Refactored the selection tracking to be in the document now

Filtering should work reliably now. No "sticking" of entries
Fixed #42. Deleted entries now result in desolation.

MacPass/MPOutlineView.m

@@ -0,0 +1,21 @@
+//
+//  MPOutlineView.m
+//  MacPass
+//
+//  Created by Michael Starke on 23.07.13.
+//  Copyright (c) 2013 HicknHack Software GmbH. All rights reserved.
+//
+
+#import "MPOutlineView.h"
+#import "MPNotifications.h"
+
+@implementation MPOutlineView
+
+- (BOOL)becomeFirstResponder {
+  [[NSNotificationCenter defaultCenter] postNotificationName:MPDidBecomeFirstResonderNotification
+                                                      object:self
+                                                    userInfo:nil];
+  return YES;
+}
+
+@end