[modules/vault] Add a new password vault module ("pass")

Add a new module that can be used to copy passwords from a password
store into the clipboard.

Currently, only "pass" is supported.

As long as only bumblebee is used, it will also show which password is
currently in the clipboard and how long it will still stay there.

bumblebee/popup_v2.py

@@ -13,14 +13,27 @@ except ImportError:
 
 import functools
 
-
 class PopupMenu(object):
-    def __init__(self):
-        self._root = tk.Tk()
-        self._root.withdraw()
-        self._menu = tk.Menu(self._root)
-        self._menu.bind("<FocusOut>", self._on_focus_out)
-        self._menu.bind("<Leave>", self._on_focus_out)
+    def __init__(self, parent=None, leave=True):
+
+        if not parent:
+            self._root = tk.Tk()
+            self._root.withdraw()
+            self._menu = tk.Menu(self._root, tearoff=0)
+            self._menu.bind("<FocusOut>", self._on_focus_out)
+        else:
+            self._root = parent.root()
+            self._root.withdraw()
+            self._menu = tk.Menu(self._root, tearoff=0)
+            self._menu.bind("<FocusOut>", self._on_focus_out)
+        if leave:
+            self._menu.bind("<Leave>", self._on_focus_out)
+
+    def root(self):
+        return self._root
+
+    def menu(self):
+        return self._menu
 
     def _on_focus_out(self, event=None):
         self._root.destroy()
@@ -29,13 +42,15 @@ class PopupMenu(object):
         self._root.destroy()
         callback()
 
+    def add_cascade(self, menuitem, submenu):
+        self._menu.add_cascade(label=menuitem, menu=submenu.menu())
 
     def add_menuitem(self, menuitem, callback):
         self._menu.add_command(label=menuitem, command=functools.partial(self._on_click, callback))
 
-    def show(self, event):
+    def show(self, event, offset_x=0, offset_y=0):
         try:
-            self._menu.tk_popup(event['x'], event['y'])
+            self._menu.tk_popup(event['x'] + offset_x, event['y'] + offset_y)
         finally:
             self._menu.grab_release()
         self._root.mainloop()