title: Import from a dictionary as a multi-index pd.DataFrame
body: <p>I have a dictionary, which calls for multi-indexing like the following:</p>
  
  <pre><code>dict = {'Main1' : {'A1' : {'a1' : 0}, 
                     'A2' : {'a2' : 15}, 
                     'A3' : {'a3' : 22}, 
                     'A4' : {'a4' : 130}},
          'Main2' : {'B1' : {'b1' : 150},
                     'B2' : {'b2' : 30},
                     'B3' : {'b3' : 1}}}
  </code></pre>
  
  <p>And I would like to have it imported on Python as a pandas DataFrame like this :</p>
  
  <pre><code>col1     col2   col3   col4
  Main 1   A1     a1     0
  Main 1   A2     a2     15
  Main 1   A3     a3     22
  Main 1   A4     a4     130
  Main 2   B1     b1     150
  Main 2   B2     b2     30
  Main 2   B3     b3     1
  </code></pre>
  
  <p>Is that even possible or should I try to find another way to import my data ?</p>