[CLI] Fix for portrait parsing

Fix for avg sprites

Update version to v0.18.0

- Updated dependencies

Update version to v0.17.4

Update AssetStudioGUI.csproj

Update CHANGELOG.md

Update version to v0.17.3

Update version to v0.17.2

- Updated projects and dependencies

Update readme files, add CHANGELOG.md

Don't use ImageSharp for texture processing

- returned to System.Drawing
(ImageSharp is a good lib, but too slow for such app, IMO)