Change format of extracted tags array

The current format of the extracted terms is an array with the key as the term id and the value as the name of the term.

array(453 => 'foo', 23 => 'bar');

This makes is impossible to alter this array to add metadata. The format should be changed to look like this:

array(
  0 => array(
    'name' => 'foo',
    'extracted_tid' => 453,
  ),
  1 => array(
    'name' => 'bar',
    'extracted_tid' => 23,
  ),
);