Version 3.1: Implemented full C++ compliance, eliminated `stdlib.h` d…

…ependency.

Removed a previously added scanline unbiasing since its positive effect was a compiler-dependent statistical error.

Fixed a bug with bit-depth conversions (e.g., 16-bit to 8-bit).

Fixed `sign conversion`, `nullptr`, and other compiler warnings.

Optimized dithering function.

Added 8-bit input gamma correction optimization.

Added optional gamma correction bypass for alpha-channel (`AlphaIndex`).

LANCIR: implemented WebAssembly SIMD128 support.

Improved documentation.

Version 3.0.

Improved speed by 10-25% on upsizing by utilizing a special resizing function together with filter-less 2X upsizing. Does not apply to the de-interleaved (AVX) resizing.
Minor LANCIR optimization.

Version 2.9.

Removed a rarely-used half-band resizing step completely since it offers no practical performance nor quality benefits.
Optimized filter generation function (removed divisions by a constant) as filters are always post-normalized anyway. This may reduce overhead when creating thumbnail-sized images.

Version 2.8.

Fixed regression with the copy-constructor of CImageResizeVars class (previously it caused uninitialized accesses).
Removed filter length optimization as it did not reduce overhead measurably.
Optimized "peaked cosine" window function generator (removed division).
Added "unbiasing" to resizer - an unconventional approach which reduces peak error significantly, at the expense of 5% increased overhead.
Reoptimized filter parameters, now yielding an unprecedented quality.

A minor fix to sRGB gamma approximation functions.

Version 2.5 release.

Version 2.4 release.

Fixed a minor image offset on image upsizing.

Released AVIR under a permissive MIT license agreement.

Minor improvements, see Change log 2.1.