title: xlrd invalid literal for int() with base 10
body: <p>I need parse an cell which contains data format 'Tuesday, January 3, 2012 2:46pm'. The code below gives error</p>
  
  <pre><code>invalid literal for int() with base 10: 'Tuesday, January 3, 2012 2:46pm'
  </code></pre>
  
  <p>May I know what is the right way to parse this string into datetime?</p>
  
  <pre><code>book = xlrd.open_workbook(f)
  sh = book.sheet_by_index(0)
  for rx in range(1, 10):  #sh.nrows
      m = sh.row(rx)
      print datetime(xlrd.xldate_as_tuple(m[0].value, book.datemode))
  </code></pre>
  
  <hr>
  
  <p>Traceback</p>
  
  <pre><code>File "C:\Anaconda\Lib\site-packages\xlrd\xldate.py", line 67, in xldate_as_tuple
      xldays = int(xldate)
  ValueError: invalid literal for int() with base 10: 'Tuesday, January 3, 2012 2:46pm'
  </code></pre>