FIX: ipympl does not need event loop support

IPython/core/pylabtools.py

@@ -62,6 +62,7 b' del backend2gui["svg"]'
 del backend2gui["pdf"]
 del backend2gui["ps"]
 del backend2gui["module://matplotlib_inline.backend_inline"]
+del backend2gui["module://ipympl.backend_nbagg"]
 
 #-----------------------------------------------------------------------------
 # Matplotlib utilities