title: sphinx sort with sql_attr_str2ordinal at textual unicode field
body: <p>i'm using sql_attr_str2ordinal for textual field, so i can do sort. I have read the documentation that explains how it works.(using the bytes etc...) if i understand that correct, it is impossible to sort textual field by locale? How it's possible to achive that? </p>
  
  <p>Sorting example(look for č letter):
  wrong sort:
  a
  b
  c
  d
  e
  .
  .
  .
  z
  č</p>
  
  <p>right sort:
  a
  b
  c
  č
  d
  e
  .
  .
  .
  z</p>
  
  <p>From docs:</p>
  
  <blockquote>
    <p>Ideally the strings should be sorted differently, depending on the
    encoding and locale. For instance, if the strings are known to be
    Russian text in KOI8R encoding, sorting the bytes 0xE0, 0xE1, and 0xE2
    should produce 0xE1, 0xE2 and 0xE0, because in KOI8R value 0xE0
    encodes a character that is (noticeably) after characters encoded by
    0xE1 and 0xE2. Unfortunately, Sphinx does not support that at the
    moment and will simply sort the strings bytewise.</p>
  </blockquote>