ticket 1650 - compute accurate translation statistics
    
    ticket 1650 (https://fedorahosted.org/freeipa/ticket/1650) has
    an extensive discussion of the issues, please refer to that.
    
    This patch does the following:
    
    * does not count fuzzy translations when computing translation
      statistics via the "msg-stats" make target in install/po
    
    * adds a new make target called "pull-po" which pulls updated po files
      from Transifex (configure.ac includes some trailing whitespace fixes)
    
    * turns off the generation of fuzzy translation suggestions during the
      message merge phase.