[Release Ver 1.0] Fixed some minor bugs

[DONE]
- Bug fixed
- Set Appropriate parameter values for confirm window & toast
- DELETED global THREAD_ACTIVE stuff from program : inf-loop will be HANDLED BY GUNICORN
- Added index.html to hold API Document

[TODO]
- Update API Document to be more intuitive
- Print Stacktrace for error
- Get rid of some irrelevant Error Code/Messages
- Error code for OtherException is no more needed
- Auto toggle to full-screen mode