Various usability improvements (#665)

* Set password creator window title

* Fix TODO, help url is read from Info.plist instead of a string literal

* Remove width constraint for 'Set Defaults' button of password generator so text is not cropped

* Improve keyboard shortcuts
New entries can be created using cmd + n, while cmd + shift + n creates new groups. Creating new databases is probably done too rarely to warrant a keyboard shortcut.
Additionally the 'New' menu item now has a submenu containing actions to create new entries, groups and databases (fixing #405).

* Hook up keyboard shortcut cmd + backspace to delete action

* Use shorter date format in inspector and add special output for distant future

* Show date picker when expiration is activates for either groups or entries but no date set

* Prompt for key file pops up automatically when the field is selected using tab

* Focus title field when new groups are created (#606).

* Rename search method so text fields don't capture it (#531)

* Don't show empty tags

* Remove menu item used for debugging.

MacPass/MPGroupInspectorViewController.h

@@ -36,4 +36,5 @@
 @property (weak) IBOutlet NSPopUpButton *autotypePopupButton;
 @property (weak) IBOutlet HNHUIRoundedTextField *autotypeSequenceTextField;
 
+- (void)registerNotificationsForDocument:(MPDocument *)document;
 @end