The soundness release

Added

• Support for ./libdxcompiler.dynlib on MacOS (#8);
• Optional path or directory argument for DXC/DXIL library (#12);
• Slice API (.as_slice(), .as_mut_slice()) for DxcBlob (#16).

Fixed

• Free native arrays, BSTR and DxcIncludeHandlerWrapper that were previously leaked (#10);
• Treat BSTR as wide string (32-bit characters) instead of UTF-16 on Linux (#10);
• Leave trailing null-character on wide strings (#13);
• Pin include blob source instead of Rc'ing it (#14).

Updated

• Update rspirv to 0.7.0 (#7);
• Update libloading to 0.7.0 (#15).