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.
I added this in the  settings.py, 
```python
language_folder = QDir(":/frontend/qtcommon/languages").entryList()
for languages in language_folder:
````
But it seems that no files are read in. Do you know how to solve it?