Fix #476 Auto language changing function finished.

Fixes issue#476.
If the user does not have the freeseer.conf file, the function will detect the system location for default language.
If there is a config file, the language setting in that file will have higher priority.
For Chinese, If the location is not zh_CN, Traditional Chinese will be used.
If there is no translation for the system location, English will be used.
Hmm, every resource I find online about locales says that Japan uses `ja_JP`, even at the OS level. For example, [this SO thread](http://stackoverflow.com/questions/3191664/list-of-all-locales-and-their-short-codes) shows locales for Windows (ja-JP, which explains the dash by @Promm) and Linux (ja_JP).