1. Update documentations for the package and for the different methods
2. Add vignettes to compare the different bootstrap types for better bug fixes
3. Add vignettes to explain the bootstrap algorithms
4. Support conditioning variable (e.g., treatment) for case bootstrap
5. Add tests for the helper functions for transforming residuals and REB resampling
6. Group three residual bootstrap as one type, and add additional specification
7. Support for parallel processing
