* updated settings with 'ALLOWED_HOSTS'
* updated MEDIA_ROOT and STATIC_ROOT of settings_production.py
* updated login.html with 'password-reset' style
* updated profile.html with transcript display
* updated about.html with alert warning information
* updated introduction with poster download link
* updated activation_email subject and content template
* updated password_reset_email subject and content template
* fixed a typo in 400.html
* small update to profile_update_done btn style
* fixed FieldFile import problem of account/extra.py
* updated models.py and added 'help_text' to transcript field
* using 'get_object_or_404' in views.py instead of simply get method
updated locale zh_CN messages
* updated transcript help_text of account/models.py
* updated ValidationError message and used named string of account/extra.py
* small changes to 'profile.html' and 'profile_update.html'
* added class Meta to notice/models.py/NoticeAttachment