In memory images for textures.

[ikeough]

BACKGROUND:
The API for creating textures for materials in Elements currently takes a relative file path and writes an image file to disk internally. This will not work for wasm scenarios where disk i/o operations are forbidden.

DESCRIPTION:
This pull request adds two new APIs to Material, enabling the user to build materials from byte[] and from Image<Rgba32> objects. Additionally, it extends the current relative path support to more robust Uri support, including absolute and relative file paths using file://, and protocols like http:// and https://.

TESTING:

• New tests are added that get images from the web to be used as textures.

REQUIRED:

• All changes are up to date in CHANGELOG.md.

---

This change is 

[serenayl]

Reviewed 8 of 8 files at r1, all commit messages.
Reviewable status: complete! 1 of 1 approvals obtained