[XML-SIG] SAX2: saxlib 1.0 fixes

[Lars Marius Garshol]

  - We haven't defined what kind of argument setLocale should take,
  partly because no parsers actually used it at the time. However, now
  xmlproc supports localization and expat has what it needs to start
  doing so (but at the moment only supports English and seems to have
  no way of setting the locale (at least the version in the CVS tree)).

  We need to take the following into account here:
  
    - xmlproc: Uses case-insensitive ISO 3166 language codes
    - Java locales: Uses a combination of lower-case ISO 639 country 
    codes and upper-case ISO 3166 language codes
    - Python locale module: Uses the ANSI C library, which seems to be
    missing in my copy of K&R, and the module documentation doesn't
    explicitly say what the locale name is, but from the examples it 
    appears to be either ISO 3166 or ISO 639 codes.
    - expat: How this will work, and if it ever will is unclear.
 
  With this in mind I propose that setLocale should take a pair of
  case-insensitive ISO 3166 and ISO 639 codes. xmlproc will then
  ignore the country code, the JPython driver will do case conversion
  and pass a java.util.Locale object to JavaSAX and hopefully this
  will work with expat as well.


  - The InputSource interface has been left out of PySAX, and should
  be introduced now, as that solves a problem with EntityResolver and
  also since Python will be getting Unicode support soon. If we agree
  on this I'll make a draft and start a separate thread on this.


  - The PySAX EntityResolver returns a system identifier, whereas the
  Java version returns an InputSource. (Thanks to Paul Prescod for
  pointing out the problems with this.) For consistency, and also to
  enable users to provide custom protocol support, I think PySAX
  should follow suit. Is anyone against this?


  - The get method on AttributeList is missing if AttributeList is to
  behave exactly as built-in dictionaries.  Should be added. (Thanks
  to Neelakantan Krishnaswami for spotting this one.)


--Lars M.