- Added `lzss_decompress_simple` function for LZSS decompression in `lzss.rs`.
- Introduced `XorState` struct and `xor_stream` function for XOR decryption in `xor.rs`.
- Updated `mod.rs` to include new LZSS and XOR modules.
- Refactored `parse_library` function in `parse.rs` to utilize the new XOR decryption functionality.
- Cleaned up and organized code in `lib.rs` by removing redundant functions and structures.
- Added tests for new functionality in `tests.rs`.
