Py3k

  * Added support for Python 3.3, dropped support for 2.5.
  * All string outputs in 2.6 and 2.7 are unicode objects with UTF-8 encoding.
  * Added exempi module, a low-level ctypes interface to exempi library.
  * Most XMPMeta methods that formerly returned bool now raise exceptions in
    case of failure, except for "does_property_exist", "does_array_item_exist".
  * Added timezone support for datetime routines.
  * Added delete_localized_text method to XMPMeta