title: Dynamic dictionary entry tkinter
body: <p>I'm trying to make a basic GUI in tkinter but I want it to be dynamic.
  The end goal is to have a nested dictionary populated by this GUI and that the user can add as many items as he/she want. 
  I managed to enter a full <em>single</em> dictionary with some simple (and pretty repetetive) code:</p>
  
  <p>for example:
  Edit</p>
  
  <pre><code>from Tkinter import *
  
  top = Tk()
  L1 = Label(top, text="User Name")
  L1.pack( side = LEFT)
  E1 = Entry(top, bd =5)
  E1.pack(side = RIGHT)
  
  top.mainloop()
  </code></pre>
  
  <p>Now im looking for a way for the GUI to have a button (like a + sign) that will allow the user to open another single or a set of entries each time he/she presses the button and populate the dictionary accordingly.
  Any Ideas?</p>