title: How to access QGIS menu items using python
body: <p>I've managed to put together some python code that loads some point data from a csv and displays it on the screen.  However, I woul now like to create some Voronoi polygons from the points using the Voronoi polygon tool that is listed under the menu Vector->Geometry Tools -> Voronoi Polygons (I'm using QGIS version 2.4.0).  Is there a python method that allows access to the drop down menu items?  If somebody could point towards and similar example that would be appreciated. I would like to add the voroni polygon process to the code below.</p>
  
  <pre><code>#--- Load a csv file and set CRS
  #---1 Reference library
  from PyQt4.QtGui import *
  from PyQt4.QtCore import *
  from qgis.core import *
  from qgis.utils import iface
  
  #---  2 Turn of the CRS dialog box
  s = QSettings()
  oldValidation = s.value( "/Projections/defaultBehaviour")
  s.setValue( "/Projections/defaultBehaviour", "useGlobal" )
  
  #--- 3 Set file name here
  InFlnm='Test.csv'
  
  #--- 4  Set pathname here
  InDrPth='C:/_Work/PyQGIS/Test/'
  
  #--- 5 Build file name an path for uri
  InFlPth="file:///"+InDrPth+InFlnm
  
  #---  6 Set import Sting here note only need to set x and y other come for free
  uri = InFlPth+"?delimiter=%s&amp;xField=%s&amp;yField=%s" % (",","x","y")
  
  #--- 7 Load point layer
  bh = QgsVectorLayer(uri, InFlnm, "delimitedtext")
  
  #--- 8 Set CRS - this does not appear to work not sure why but no matter the damn thing loads!
  bh.setCrs(QgsCoordinateReferenceSystem(4326, QgsCoordinateReferenceSystem.EpsgCrsId))
  
  #--- 9 Display the layer into QGIS (but it asks for CRS before displaying_
  QgsMapLayerRegistry.instance().addMapLayer(bh)
  
  #--- 10 turn CRS dialog box back on again
  s.setValue( "/Projections/defaultBehaviour", oldValidation )
  </code></pre>