title: UITableView: move cell to a position to another with drag & drop
body: <p>i have a table with 3 section (section one, section two and section three). I would like implement a mechanism to change a cell's position with drag &amp; drop (inside same section or from a section to another).</p>
  
  <p>Example 1:
  In section one i have two rows (sec1_row1 and sec1_row2). In section two i have one row (sec2_row1) by drag &amp; drop function i would like invert the sec1_row2 with sec2_row1. I would like select the sec2_row1, drag it on sec2_row1 and drop it so the rows are inverted.</p>
  
  <p>I would like that this feature will be also available for rows of same section.</p>
  
  <p>What is the best way to implement this feature? </p>
  
  <p>Thanks in advance.</p>