title: How to swap adjacent bytes in a string of hex bytes (with or without regular expressions)
body: <p>Given the string (or any length string with an even-number of word pairs):
  "12345678"</p>
  
  <p>How would I swap adjacent "words"?</p>
  
  <p>The result I want is
  "34127856"</p>
  
  <p>As well as, when that's done I need to swap the longs.
  The result I want is:
  "78563412"</p>