Extracted context menu operations into MPContextMenuHelper

Removed private declarations as they aren't needed for the compiler anymore
Fixed drawing order in MPPopupImageView
Fixed #7 Error occurred due to duplicate shortcut.
Copy Password now is bound to ⌘+⌥+C

MacPass/MPAppDelegate.h

@@ -8,16 +8,6 @@
 
 #import <Cocoa/Cocoa.h>
 
-typedef enum {
-  MPContextMenuCreate = 1<<0,
-  MPContextMenuDelete = 1<<1,
-  MPContextMenuCopy = 1<<2,
-  MPContextMenuMinimal = MPContextMenuCreate | MPContextMenuDelete,
-  MPContextMenuFull = MPContextMenuMinimal | MPContextMenuCopy,
-}MPContextMenuItemsFlags;
-
-@class MPDatabaseDocument;
-
 @interface MPAppDelegate : NSObject <NSApplicationDelegate>
 
 @property (retain) IBOutlet NSWindow *passwordCreatorWindow;
@@ -26,10 +16,4 @@ typedef enum {
 
 - (NSString *)applicationName;
 
-/*
- Creates an array of menuitems to be used as a menu
- Automatically sets up actions, so you need to take care of the responder chain
- */
-- (NSArray *)contextMenuItemsWithItems:(MPContextMenuItemsFlags)flags;
-
 @end