* add unittests
* lint
* modify .gitignore, remove useless files
* remove emtpy.py and generate it when use
* Update according to comments
1. Use tempfile
2. Delete inference test (which will be tested in each codebase)
3. Refine calibration test
* update annotation
* Add export_info
* Reduce data scale, fix assert
* update json blank line
* add backend check
