Log Message:
Update mecab to 0.993.

2012-01-27 MeCab 0.993
* Fix to works well for MeCab::Tagger::formatNode()
* To reduce stack size, save almost of local variables(arrays) to heap.

2012-01-14 MeCab 0.992
* Fix typos in source codes.

2012-01-14 MeCab 0.991
* Fix parse error with null strings or space strings.
* Fix failure for creation of user dictionaries.

2011-12-24 MeCab 0.99
* Add MeCab::Model MeCab::Lattice classes.
  Improve usabilities on multi threads environment. Multiple threads can parse
  with shareing same dictionary.
* Remove function for automatic dictionary reference share when refereing same
  dictionaly (You can do same works with MeCab::Model).
* Add function for atomic dictionaly update in parsing. Model::swap()
* Change Windows version to Unicode binary.
* Remove experimental online learning, HMM and EM learning codes.
* Remove MeCab::Node:(begin|end)_node_list members.
* minor bug fixes.