title: Converting given list into dataframe
body: <p>I have the following list:              </p>
  
  <pre><code>$id1
  $id1[[1]]
           A              B               
          "A"            "B"                
  $id1[[2]]
           A             B 
          "A"           "A1" 
  $id2
  $id2[[1]]
           A              B               
          "A2"           "B2" 
  </code></pre>
  
  <p>In R-pastable form:</p>
  
  <pre><code>dat = structure(list(SampleTable = structure(list(id2 = list(structure(c("90", "7"), .Names = c("T", "G")), structure(c("90", "8"), .Names = c("T", "G"))), id1 = structure(c("1", "1"), .Names = c("T", "G"))), .Names = c("id2", "id1"))), .Names = "SampleTable") 
  </code></pre>
  
  <p>I want this given list to be converted into following dataframe:</p>
  
  <pre><code>id1   A    B
  id1   A    A1 
  id2   A2   B2 
  </code></pre>