title: "app" from appJar undefined when using functions from a seperate module
body: <p>I have the code below that consist of the GUI for a program and currently two separate functions. In order to keep my main.py file somewhat neat I wanted to separate my functions into other files. However when I do this and import said file into main.py, when the code is run and I try to use the events related to imported functions, I get an Error that says "app" undefined. The problem is I am not sure how to define it in this case so that it would work.</p>
  
  <p>Question is: How can I define app when using functions from another file?</p>
  
  <p><strong>Full Error:</strong> Traceback (most recent call last):
    File "C:\Users\Jason Smit\AppData\Local\Programs\Python\Python36-32\lib\tkinter__init__.py", line 1702, in <strong>call</strong>
      return self.func(*args)
    File "C:\Users\Jason Smit\PycharmProjects\Project-X\venv\lib\site-packages\appJar\appjar.py", line 3494, in 
      return lambda *args: funcName(param)
    File "C:\Users\Jason Smit\PycharmProjects\Project-X\menu_events.py", line 10, in toolbar
      if app.exitFullscreen():
  NameError: name 'app' is not defined</p>
  
  <pre><code>from appJar import gui
  
  # Global Constants:
  
  FILE_MENUS = ["Open", "Save", "Save as...", "Export", "Close"]
  HELP_MENUS = ["Help", "Getting Started", "Settings", "Submit Feedback", "About"]
  
  
  def login(btn):
      if btn == "Unlock":
          app.infoBox("Success", "Access granted\n Welcome User")
          app.hideSubWindow("Sub1")
          app.show()
      return
  
  # Holds event handlers for toolbar
  
  
  def toolbar(btn):
      print(btn)
      if btn == "LOGOUT":
          app.hide()
          app.showSubWindow("Sub1")
      elif btn == "FULL-SCREEN":
          if app.exitFullscreen():
              app.setToolbarIcon("FULL-SCREEN", "FULL-SCREEN")
          else:
              app.setSize("fullscreen")
              app.setToolbarIcon("FULL-SCREEN", "FULL-SCREEN-EXIT")
  
  
  ###################
  # GUI starts here # 
  ###################
  
  
  with gui("Project-X", "1700x1000") as app:
      app.setBg("white")
      app.setIcon("app_icon.ico")  # App icon
  
      # Subwindow for user login
      with app.subWindow("Sub1", "Login",):
          app.setBg("white")
  
          # Empty left container (To help get login in center.)
          with app.frame("LEFT", row=0, column=0, sticky='NEW', stretch='COLUMN'):
              """"""
          # Login container/gui
  
          with app.frame("CenterTop", row=0, column=1, sticky='NEW', stretch='column'):
              app.setBg("white")
              with app.labelFrame("Login"):
                  app.setBg("white")
                  app.setSticky("ew")
                  # Login widget setup
                  app.addLabel("Usr", "Name", 0, 0)
                  app.addEntry("Name", 0, 1)
                  app.addLabel("Pwd", "Password", 1, 0)
                  app.addSecretEntry("Password", 1, 1)
                  app.addNamedButton("Submit", "Unlock", login, 2, 0, 2)
  
          # Empty right container (To help get login in center.)
  
          with app.frame("RIGHT", row=0, column=2,  sticky='NEW', stretch='COLUMN'):
              """"""
      # Top-level menu for main window
  
      app.addMenuList("File", FILE_MENUS, toolbar)
      app.addMenuList("Help", HELP_MENUS, toolbar)
  
      # Main navigation Toolbar
      app.addToolbar(["LOGOUT", "FULL-SCREEN"], toolbar, findIcon=True)
  
      # Tabbed page for displaying info for each category
      with app.tabbedFrame("Item Inventory"):
          app.startTab("Category_1")
          app.addLabel("l1", "Test for category tab 1")
          app.stopTab()
  
          app.startTab("Category_2")
          app.addLabel("l2", "Test for category tab 2")
          app.stopTab()
  
      # Start application from login sub window
      app.go(startWindow="Sub1")
  </code></pre>