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/MPKeyfilePathControlDelegate.m

@@ -29,7 +29,18 @@
 }
 
 - (void)pathControl:(NSPathControl *)pathControl willDisplayOpenPanel:(NSOpenPanel *)openPanel {
-  
+}
+
+- (void)pathControlDidBecomeKey:(NSPathControl *)control {
+  if(control.URL) return;
+
+  dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
+    NSOpenPanel *panel = [NSOpenPanel openPanel];
+    panel.allowedFileTypes = control.allowedTypes;
+    if([panel runModal] != NSModalResponseOK) return;
+
+    control.URL = panel.URL;
+  });
 }
 
 @end