Upgrade to Unicode 6.0.0.

makeunicodedata.py: download all data files from unicode.org,
  switch to extracting Unihan data from zip file.
  Read linebreakprops and derivednormalizationprops even for
  old versions, even though they are not used in delta records.
test:unicode.py: U+11000 is now assigned, use U+14000 instead.