Notes:

Release Name: 1.8.1

Notes:

Changes:
- Fixes to Preprocessing
- NIfTI to DICOM writing improvements
- Registration improvements (rigid and deformable added to CLI and GUI)
- Bias correction improvements
- Added functionality in Utilities
- Label statistics (generic and BraTS-specific)
- Casting fixes
- Fixes to Feature Extraction
- Fixes to a lot of brain-cancer applications:
- PCA calculation
- Perfusion derivatives fixes
- Diffusion derivatives
- Survival fixes
- Recurrence fixes
- Pseudoprogression fixes
- Generic GUI bug fixes and improvements