Update Sympy_printing extension load

Change 

%loaf_ext sympyprinting
to
%load_ext sympy.interactive.ipythonprinting

examples/notebooks/SymPy Examples.ipynb

@@ -24,7 +24,7 b''
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "%load_ext sympyprinting\n",
+      "%load_ext sympy.interactive.ipythonprinting\n",
       "%pylab inline\n",
       "\n",
       "from __future__ import division\n",
@@ -655,4 +655,4 b''
    "metadata": {}
   }
  ]
-}
  No newline at end of file
+}