- Implemented range coder in `rangecoder.c` and `rangecoder.h` for efficient encoding/decoding.
- Added RLE90 decoding in `rle90.c` for handling StuffIt method 1.
- Introduced `stuffit.h` and `stuffit_internal.h` to define compression methods and internal structures.
- Implemented x86 address transformation in `x86.c` for StuffIt X preprocessing.
- Updated CMakeLists to include new test data files for various StuffIt methods.
- Created comprehensive tests in `stuffit.cpp` for validating decompression of multiple StuffIt formats.
- Added binary test data for StuffIt methods including compress, method 13, arsenic, and StuffIt X variants.
