add `%matplotlib notebook`

alias for `%matplotlib nbagg`

IPython/core/pylabtools.py

@@ -22,6 +22,7 b" backends = {'tk': 'TkAgg',"
             'qt5': 'Qt5Agg',
             'osx': 'MacOSX',
             'nbagg': 'nbAgg',
+            'notebook': 'nbAgg',
             'inline' : 'module://IPython.kernel.zmq.pylab.backend_inline'}
 
 # We also need a reverse backends2guis mapping that will properly choose which

IPython/kernel/zmq/eventloops.py

@@ -40,6 +40,7 b' def _notify_stream_qt(kernel, stream):'
 loop_map = {
     'inline': None,
     'nbagg': None,
+    'notebook': None,
     None : None,
 }