Merge pull request #22 from van51/master

Added lang_detect backend for the demo
implement application/language_detect web demo / add a new panel type 'about' / add a new template type 'text'
Merge pull request #23 from ZhengyangL/application/lang_detect

implement application/language_detect web demo / add a new panel type 'about' / add a new template type 'text'
Changed prompt and about in language detection demo