Log Message:
libpinyin: Update to 2.6.0

* Enable libzhuyin.

Changelog:
version 2.6.0
* bug fixes

version 2.4.92
* update pinyin data
* bug fixes

version 2.4.91
* improve full pinyin auto correction
* bug fixes

version 2.3.0
* update pinyin data

version 2.2.2
* minor fixes

version 2.2.1
* fixes predicted candidates

version 2.2.0
* bug fixes

version 2.1.91
* fixes zhuyin parsers;

version 2.1.0
* support sort option in pinyin_guess_candidates function;

version 2.0.92
* reduce memory consumption after imported user dictionary;

version 2.0.91
* merge libzhuyin code;

version 2.0.0
* the first official release of 2.0.x;
* fixes autoconf;

version 1.9.92
* fixes crash in double pinyin;

version 1.9.91
* multiple sentence candidates;

version 1.7.0
* fixes build on FreeBSD;
* update cmake files;

version 1.6.91
* change license to GPLv3+;
* import open-gram dictionary and remove pinyin tones;
* add some checks when load data from file;

version 1.6.0
* bug fixes.

version 1.5.91
* change pinyin/phrase tables to use dbm.
* enhance pinyin key representation and pinyin parsers.

version 1.2.0
* bug fixes.

version 1.1.91
* support Kyoto Cabinet as alternative to Berkeley DB.
* improve multiple dictionaries support feature.

version 1.1.0
* support to export user phrases.