add simplified chinese translation
Merge pull request #93 from haobug/chinese_translate

add simplified chinese translation
Fix #90 captcha check, new version released

This removes the custom implementation of the captcha check and uses the
helper function that is provided by the captcha plugin instead. This
helper function has been available since January 2009, therefore this
changed version should also work with older versions of the captcha plugin.
Merge branch 'master' of https://github.com/dokufreaks/plugin-discussion