title: cx_freeze doesn't create .exe file on a python script that uses subprocess to run other python scripts
body: <p>I am trying to freeze a python program that is just a menu with choices to run other python scripts.  I am using subprocess to run each script choice in the main program (menu).  The program itself runs fine, but when I try to create the executable using cx_freeze, the creation process seems to be interrupted, and the resulting .exe file does not run any of the subprocesses.  I have tried to use other methods to call the chosen python scripts, such as os and call, but can't get them to work.  Please help me so that I can get a working .exe file.  This is part of the main script using subprocess:</p>
  
  <pre><code>import tkinter as tk
  from tkinter import Frame, Button, Label
  import subprocess
  import sys
  import os    
  
  class menu(Frame):
      def __init__(self, master=None):
          Frame.__init__(self, master)
          self.grid()
          self.mymaster = master   
          self.widgets()
  
      def widgets(self):
          self.menu_container()
          self.fill0_frame()
          self.title()
          self.bottom_frame()
          self.play_or_quit())
  
      def menu_container(self):
          self.menu_container = tk.Toplevel(self)
  
      ...
      ...
      ....
      def play_or_quit(self):
          self.play_or_quit = Frame(self.bottom_frame,width=100,background="grey")
          self.play_or_quit.grid(row=2,column=5)
          self.button1 = tk.Button(self.play_or_quit, command = import_cw2)
          self.button1_name = "childwindow2"
          self.button1.configure(text=self.button1_name,             background="violet",width=16)
          self.button1.grid(row=17,column=10,sticky = "ES")
          self.button2 = tk.Button(self.play_or_quit, command = import_cwp4)
          self.button2_name = "childwindowprimes4"
          self.button2.configure(text=self.button2_name, background="pink",width=16)
          self.button2.grid(row=18,column=10,sticky = "ES")
          self.button3 = Button(self.play_or_quit, command = import_TSF) #height=1,width=2)
          self.button3_name = "The Seiji Factor"  
          self.button3.configure(text=self.button3_name, background="tan",width=16)
          self.button3.grid(row=19,column=10,sticky = "ES")   
          self.button4 = Button(self.play_or_quit, command = self.finished, height=1,width=2)
          self.button4_name = "Quit"  
          self.button4.configure(text=self.button4_name, background="red",width=16)
          self.button4.grid(row=20,column=10,sticky= "ES")
  ...
  def import_cw2(): #,event
      theproc = subprocess.Popen([sys.executable, "cw2gameframes.py"])
      theproc.communicate()       
  
  def import_cwp4():
      theproc2 = subprocess.Popen([sys.executable, "cwp4gameframes.py"])
      theproc2.communicate()
  
  def import_TSF():
      theproc = subprocess.Popen([sys.executable, "SeijiFactorgameframes.py"])
      theproc.communicate()         
  
  if __name__=='__main__':
      root = tk.Tk()
      root.withdraw()
      application = menu(root)
      root.mainloop()
  </code></pre>