add 'osx' to known pylab backends, fix pylab mode with MacOSX backend

closes gh-202

IPython/core/magic.py

@@ -3371,7 +3371,7 b' Defaulting color scheme to \'NoColor\'"""'
         Parameters
         ----------
         guiname : optional
-          One of the valid arguments to the %gui magic ('qt', 'wx', 'gtk' or
+          One of the valid arguments to the %gui magic ('qt', 'wx', 'gtk', 'osx' or
           'tk').  If given, the corresponding Matplotlib backend is used,
           otherwise matplotlib's default (which you can override in your
           matplotlib config file) is used.

IPython/lib/inputhook.py

@@ -28,6 +28,7 b" GUI_QT = 'qt'"
 GUI_QT4 = 'qt4'
 GUI_GTK = 'gtk'
 GUI_TK = 'tk'
+GUI_OSX = 'osx'
 
 #-----------------------------------------------------------------------------
 # Utility classes
@@ -310,6 +311,7 b' def enable_gui(gui=None):'
     one.
     """
     guis = {None: clear_inputhook,
+            GUI_OSX: lambda app=False: None,
             GUI_TK: enable_tk,
             GUI_GTK: enable_gtk,
             GUI_WX: enable_wx,

IPython/lib/pylabtools.py

@@ -30,6 +30,7 b" backends = {'tk': 'TkAgg',"
             'wx': 'WXAgg',
             'qt': 'Qt4Agg', # qt3 not supported
             'qt4': 'Qt4Agg',
+            'osx': 'MacOSX',
             'inline' : 'module://IPython.zmq.pylab.backend_inline'}
 
 #-----------------------------------------------------------------------------